Carrier 48Tc D08 Users Manual 48tc_p1 36

48TC*D08 48tc-3sm

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48TC*D08---D14
Nominal 7.5 to 12.5 Tons
With Puron® (R---410A) Refrigerant

Service and Maintenance Instructions
TABLE OF CONTENTS

SAFETY CONSIDERATIONS

SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . 1

Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical
components. Only trained and qualified service personnel
should install, repair, or service air-conditioning
equipment. Untrained personnel can perform the basic
maintenance functions of replacing filters. Trained service
personnel should perform all other operations.

UNIT ARRANGEMENT AND ACCESS . . . . . . . . . . . 2
SUPPLY FAN (BLOWER) SECTION . . . . . . . . . . . . . . 4
COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
PURONR (R-- 410A) REFRIGERANT . . . . . . . . . . . . . . 8
COOLING CHARGING CHARTS . . . . . . . . . . . . . . . . 10
CONVENIENCE OUTLETS . . . . . . . . . . . . . . . . . . . . 16
SMOKE DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . 17
PROTECTIVE DEVICES . . . . . . . . . . . . . . . . . . . . . . . 24
GAS HEATING SYSTEM . . . . . . . . . . . . . . . . . . . . . . 25
CONDENSER COIL SERVICE . . . . . . . . . . . . . . . . . . 35
PREMIERLINKt CONTROL . . . . . . . . . . . . . . . . . . . 36
RTU-- MP CONTROL SYSTEM . . . . . . . . . . . . . . . . . . 44
ECONOMI$ER SYSTEMS . . . . . . . . . . . . . . . . . . . . . . 57
WIRING DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . 66
PRE-- START-- UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
START-- UP, GENERAL . . . . . . . . . . . . . . . . . . . . . . . . 69
START-- UP, PREMIERLINK CONTROL . . . . . . . . . . 71
START-- UP, RTU-- MP CONTROL . . . . . . . . . . . . . . . . 71
OPERATING SEQUENCES . . . . . . . . . . . . . . . . . . . . . 75
FASTENER TORQUE VALUES . . . . . . . . . . . . . . . . . 85
APPENDIX I. MODEL NUMBER SIGNIFICANCE . 87
APPENDIX II. PHYSICAL DATA . . . . . . . . . . . . . . . . 88
APPENDIX III. FAN PERFORMANCE . . . . . . . . . . . 90
APPENDIX IV. WIRING DIAGRAM LIST . . . . . . . . 96
APPENDIX V. MOTORMASTER SENSOR
LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
UNIT START-UP CHECKLIST . . . . . . . . . . . . . . . . . . 98

When working on air-conditioning equipment, observe
precautions in the literature, tags and labels attached to
the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for unbrazing operations.
Have fire extinguishers available for all brazing
operations.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for brazing operations. Have
fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions attached to
the unit. Consult local building codes and National
Electrical Code (NEC) for special requirements.
Recognize safety information. This is the safety-- alert
. When you see this symbol on the unit and in
symbol
instructions or manuals, be alert to the potential for
personal injury.
Understand the signal words DANGER, WARNING, and
CAUTION. These words are used with the safety-- alert
symbol. DANGER identifies the most serious hazards
which will result in severe personal injury or death.
WARNING signifies a hazard which could result in
personal injury or death. CAUTION is used to identify
unsafe practices which may result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.

WARNING

48TC

!

!

FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect gas piping from unit when pressure testing
at pressure greater than 0.5 psig. Pressures greater
than 0.5 psig will cause gas valve damage resulting in
hazardous condition. If gas valve is subjected to
pressure greater than 0.5 psig, it must be replaced
before use. When pressure testing field-supplied gas
piping at pressures of 0.5 psig or less, a unit connected
to such piping must be isolated by closing the manual
gas valve(s).

FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in
personal injury, death and/or property damage.
Refer to the User’s Information Manual provided
with this unit for more details.
Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
appliance.
What to do if you smell gas:
DO NOT try to light any appliance.
DO NOT touch any electrical switch, or use any
phone in your building.
IMMEDIATELY call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
If you cannot reach your gas supplier, call the fire
department.

!

!

!

WARNING

UNIT ARRANGEMENT AND ACCESS
General
Fig. 1 and Fig. 2 show general unit arrangement and
access locations.
FILTER ACCESS PANEL

ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Units with convenience outlet circuits may use
multiple disconnects. Check convenience outlet for
power status before opening unit for service. Locate
its disconnect switch, if appropriate, and open it.
Tag-- out this switch, if necessary.

!

CAUTION

CUT HAZARD
Failure to follow this caution may result in personal
injury.
Sheet metal parts may have sharp edges or burrs. Use
care and wear appropriate protective clothing, safety
glasses and gloves when handling parts and servicing
air conditioning units.

WARNING

ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Before performing service or maintenance operations
on unit, turn off main power switch to unit. Electrical
shock and rotating equipment could cause injury.

WARNING

WARNING

UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
PuronR (R-- 410A) refrigerant systems operate at
higher pressures than standard R-- 22 systems. Do not
use R-- 22 service equipment or components on
PuronR refrigerant equipment.

INDOOR COIL ACCESS PANEL
C06023

Fig. 1 - Typical Access Panel Locations (Back)

2

Heating
S Heat exchanger flue passageways cleanliness
S Gas burner condition
S Gas manifold pressure
S Heating temperature rise
Economizer or Outside Air Damper

CONTROL BOX
COMPRESSOR
C08450

Fig. 2 - Typical Access Panel Location (Front)

Routine Maintenance
These items should be part of a routine maintenance
program, to be checked every month or two, until a
specific schedule for each can be identified for this
installation:
Quarterly Inspection (and 30 days after initial start)
S
S
S
S
S
S
S
S

Return air filter replacement
Outdoor hood inlet filters cleaned
Belt tension checked
Belt condition checked
Pulley alignment checked
Fan shaft bearing locking collar tightness checked
Condenser coil cleanliness checked
Condensate drain checked

S Inlet filters condition
S Check damper travel (economizer)
S Check gear and dampers for debris and dirt
Air Filters and Screens
Each unit is equipped with return air filters. If the unit has
an economizer, it will also have an outside air screen. If a
manual outside air damper is added, an inlet air screen
will also be present.
Each of these filters and screens will need to be
periodically replaced or cleaned.
Return Air Filters
Return air filters are disposable fiberglass media type.
Access to the filters is through the small lift-- out panel
located on the rear side of the unit, above the
evaporator/return air access panel. (See Fig. 1.)
To remove the filters:
1. Grasp the bottom flange of the upper panel.
2. Lift up and swing the bottom out until the panel disengages and pulls out.
3. Reach inside and extract the filters from the filter
rack.
4. Replace these filters as required with similar replacement filters of same size.

Seasonal Maintenance
These items should be checked at the beginning of each
season (or more often if local conditions and usage
patterns dictate):
Air Conditioning
S
S
S
S
S
S
S
S

Condenser fan motor mounting bolts tightness
Compressor mounting bolts
Condenser fan blade positioning
Control box cleanliness and wiring condition
Wire terminal tightness
Refrigerant charge level
Evaporator coil cleaning
Evaporator blower motor amperage

To re-- install the access panel:
1. Slide the top of the panel up under the unit top panel.
2. Slide the bottom into the side channels.
3. Push the bottom flange down until it contacts the top
of the lower panel (or economizer top).
IMPORTANT: DO NOT OPERATE THE UNIT
WITHOUT THESE FILTERS!
Outside Air Hood
Outside air hood inlet screens are permanent
aluminum-- mesh type filters. Check these for cleanliness.
Remove the screens when cleaning is required. Clean by
washing with hot low-- pressure water and soft detergent
and replace all screens before restarting the unit. Observe
the flow direction arrows on the side of each filter frame.
Economizer Inlet Air Screen
This air screen is retained by spring clips under the top
edge of the hood. (See Fig. 3.)

3

48TC

FLUE OPENING

BLOWER
ACCESS
PANEL

SUPPLY FAN (BLOWER) SECTION
22 3/8 (569 mm)

!

ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal
injury or death.
Before performing service or maintenance operations
on the fan system, shut off all unit power and tag-- out
the unit disconnect switch. Do not reach into the fan
section with power still applied to unit.

DIVIDER
OUTSIDE
AIR
HOOD

48TC

CLEANABLE
ALUMINUM
FILTER

Supply Fan (Belt--Drive)

FILTER

BAROMETRIC
RELIEF

FILTER
CAP

Fig. 3 - Filter Installation

WARNING

C08634

To remove the filter, open the spring clips. Re-- install the
filter by placing the frame in its track, then closing the
spring clips.

The supply fan system consists of a forward-- curved
centrifugal blower wheel on a solid shaft with two
concentric type bearings, one on each side of the blower
housing. A fixed-- pitch driven pulley is attached to the fan
shaft and an adjustable-- pitch driver pulley is on the
motor. The pulleys are connected using a “V” type belt.
(See Fig. 5.)

Manual Outside Air Hood Screen
This inlet screen is secured by a retainer angle across the
top edge of the hood. (See Fig. 4.)

Fig. 5 - Belt Drive Motor Mounting

C07087

Belt

C07156

Fig. 4 - Screens Installed on Outdoor-- Air Hood
(Sizes 7-1/2 to 12-1/2 Tons Shown)

To remove the screen, loosen the screws in the top retainer
and slip the retainer up until the filter can be removed.
Re-install by placing the frame in its track, rotating the
retainer back down and tighten all screws.

Check the belt condition and tension quarterly. Inspect the
belt for signs of cracking, fraying or glazing along the
inside surfaces. Check belt tension by using a spring-force
tool (such as Browning’s Part Number “Belt Tension
Checker” or equivalent tool); tension should be 6-lbs at a
5/8-in. deflection when measured at the centerline of the
belt span. This point is at the center of the belt when
measuring the distance between the motor shaft and the
blower shaft.
NOTE: Without the spring-- tension tool, place a straight
edge across the belt surface at the pulleys, then deflect the
belt at mid-- span using one finger to a 1/2-in. deflection.
Adjust belt tension by loosening the motor mounting plate
front bolts and rear bolt and sliding the plate toward the
fan (to reduce tension) or away from fan (to increase
tension). Ensure the blower shaft and the motor shaft are
parallel to each other (pulleys aligned). Tighten all bolts
when finished.

4

To replace the belt:

To align fan and motor pulleys:

1. Use a belt with same section type or similar size. Do
not substitute a “FHP” type belt. When installing the
new belt, do not use a tool (screwdriver or pry-- bar) to
force the belt over the pulley flanges, this will stress
the belt and cause a reduction in belt life.
2. Loosen the motor mounting plate front bolts and rear
bolts.
3. Push the motor and its mounting plate towards the
blower housing as close as possible to reduce the center distance between fan shaft and motor shaft.
4. Remove the belt by gently lifting the old belt over
one of the pulleys.
5. Install the new belt by gently sliding the belt over
both pulleys and then sliding the motor and plate
away from the fan housing until proper tension is
achieved.
6. Check the alignment of the pulleys, adjust if necessary.
7. Tighten all bolts.
8. Check the tension after a few hours of runtime and
re-- adjust as required.
Adjustable-- Pitch Pulley on Motor
The motor pulley is an adjustable-- pitch type that allows a
servicer to implement changes in the fan wheel speed to
match as-- installed ductwork systems. The pulley consists
of a fixed flange side that faces the motor (secured to the
motor shaft) and a movable flange side that can be rotated
around the fixed flange side that increases or reduces the
pitch diameter of this driver pulley. (See Fig. 6.)
As the pitch diameter is changed by adjusting the position
of the movable flange, the centerline on this pulley shifts
laterally (along the motor shaft). This creates a
requirement for a realignment of the pulleys after any
adjustment of the movable flange. Also reset the belt
tension after each realignment.

48TC

1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft. Make angular alignment by loosening motor from mounting.
3. Tighten fan pulley setscrews and motor mounting
bolts to torque specifications.
4. Recheck belt tension.

Fig. 6 - Supply-- Fan Pulley Adjustment

C07075

Bearings
This fan system uses bearings featuring concentric split
locking collars. The collars are tightened through a cap
screw bridging the split portion of the collar. The cap
screw has a Torx T25 socket head. To tighten the locking
collar: Hold the locking collar tightly against the inner
race of the bearing and torque the cap screw to 65-- 70
in-lb (7.4-- 7.9 Nm). (See Fig. 7.)

Check the condition of the motor pulley for signs of wear.
Glazing of the belt contact surfaces and erosion on these
surfaces are signs of improper belt tension and/or belt
slippage. Pulley replacement may be necessary.
To change fan speed:
1. Shut off unit power supply.
2. Loosen belt by loosening fan motor mounting nuts.
(See Fig. 5.)
3. Loosen movable pulley flange setscrew. (See Fig. 6.)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew to torque specifications.

Fig. 7 - Tightening Locking Collar

C08121

Motor
When replacing the motor, also replace the external-- tooth
lock washer (star washer) under the motor mounting base;
this is part of the motor grounding system. Ensure the
teeth on the lock washer are in contact with the motor’s
painted base. Tighten motor mounting bolts to 120 +/-- 12
in-- lbs.

5

48TC

Changing fan wheel speed by changing pulleys: The
horsepower rating of the belt is primarily dictated by the
pitch diameter of the smaller pulley in the drive system
(typically the motor pulley in these units). Do not install a
replacement motor pulley with a smaller pitch diameter
than provided on the original factory pulley. Change fan
wheel speed by changing the fan pulley (larger pitch
diameter to reduce wheel speed, smaller pitch diameter to
increase wheel speed) or select a new system (both
pulleys and matching belt(s)).
Before changing pulleys to increase fan wheel speed,
check the fan performance at the target speed and airflow
rate to determine new motor loading (bhp). Use the fan
performance tables or use the Packaged Rooftop Builder
software program. Confirm that the motor in this unit is
capable of operating at the new operating condition. Fan
shaft loading increases dramatically as wheel speed is
increased.
To reduce vibration, replace the motor’s adjustable pitch
pulley with a fixed pitch pulley (after the final airflow
balance adjustment). This will reduce the amount of
vibration generated by the motor/belt-- drive system.

COOLING

!

WARNING

UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
This system uses PuronR refrigerant which has higher
pressures than R-- 22 and other refrigerants. No other
refrigerant may be used in this system. Gauge set,
hoses, and recovery system must be designed to
handle Puron refrigerant. If unsure about equipment,
consult the equipment manufacturer.

Condenser Coil
The condenser coil is new NOVATION Heat Exchanger
Technology. This is an all-- aluminum construction with
louvered fins over single-- depth crosstubes.
The
crosstubes have multiple small passages through which
the refrigerant passes from header to header on each end.
Tubes and fins are both aluminum construction.
Connection tube joints are copper. The coil may be
one-- row or two-- row. Two-- row coils are spaced apart to
assist in cleaning.

TUBES

FINS

MANIFOLD
MICROCHANNELS

Fig. 8 - Microchannel Coils

C07273

Evaporator Coil
The evaporator coil is traditional round-- tube, plate-- fin
technology. Tube and fin construction is of various
optional materials and coatings (see Model Number
Format). Coils are multiple-- row.
Coil Maintenance and Cleaning Recommendation
Routine cleaning of coil surfaces is essential to maintain
proper operation of the unit. Elimination of contamination
and removal of harmful residues will greatly increase the
life of the coil and extend the life of the unit. The
following maintenance and cleaning procedures are
recommended as part of the routine maintenance activities
to extend the life of the coil.
Remove Surface Loaded Fibers
Surface loaded fibers or dirt should be removed with a
vacuum cleaner. If a vacuum cleaner is not available, a
soft non-- metallic bristle brush may be used. In either
case, the tool should be applied in the direction of the fins.
Coil surfaces can be easily damaged (fin edges can be
easily bent over and damage to the coating of a protected
coil) if the tool is applied across the fins.
NOTE: Use of a water stream, such as a garden hose,
against a surface loaded coil will drive the fibers and dirt
into the coil. This will make cleaning efforts more
difficult. Surface loaded fibers must be completely
removed prior to using low velocity clean water rinse.
Periodic Clean Water Rinse
A periodic clean water rinse is very beneficial for coils
that are applied in coastal or industrial environments.
However, it is very important that the water rinse is made
with very low velocity water stream to avoid damaging
the fin edges. Monthly cleaning as described below is
recommended.

6

Routine Cleaning of NOVATION Condenser Coil
Surfaces

Totaline Environmentally Sound Coil Cleaner Application
Equipment

To clean the NOVATION condenser coil, chemicals are
NOT to be used; only water is approved as the cleaning
solution. Only clean potable water is authorized for
cleaning NOVATION condensers. Carefully remove any
foreign objects or debris attached to the coil face or
trapped within the mounting frame and brackets. Using a
high pressure water sprayer, purge any soap or industial
cleaners from hose and/or dilution tank prior to wetting
the coil.

S 2-1/2 gallon garden sprayer
S water rinse with low velocity spray nozzle

PERSONAL INJURY HAZARD
Failure to follow this caution may result in corrosion
and damage to the unit.
Harsh chemicals, household bleach or acid or basic
cleaners should not be used to clean outdoor or indoor
coils of any kind. These cleaners can be very difficult
to rinse out of the coil and can accelerate corrosion at
the fin/tube interface where dissimilar materials are in
contact. If there is dirt below the surface of the coil,
use the Totaline environmentally sound coil cleaner as
described above.

Clean condenser face by spraying the coil core steadily
and uniformly from top to bottom, directing the spray
straight into or toward the coil face. Do not exceed 900
psig or a 45 degree angle; nozzle must be at least 12 in.
(30 cm) from the coil face. Reduce pressure and use
caution to prevent damage to air centers (fins). Do not
fracture the braze between air centers and refrigerant
tubes. Allow water to drain from the coil core and check
for refrigerant leaks prior to start-- up.

!

NOTE: Please see the NOVATION Condenser Service
section for specific information on the coil.

!

Routine Cleaning of Evaporator Coil Sufaces
Monthly cleaning with Totaline® environmentally sound
coil cleaner is essential to extend the life of coils. This
cleaner is available from Carrier Replacement parts
division as part number P902-- 0301 for one gallon
container, and part number P902-- 0305 for a 5 gallon
container. It is recommended that all round tube coil
cleaner as described below. Coil cleaning should be part
of the unit’s regularly scheduled maintenance procedures
to ensure long life of the coil. Failure to clean the coils
may result in reduced durability in the environment.
Avoid the use of
S
S
S
S

coil brighteners
acid cleaning prior to painting
high pressure washers
poor quality water for cleaning

Totaline environmentally sound coil cleaner is
non-- flammable, hypoallergenic, non-- bacterial, and a
USDA accepted biodegradable agent that will not harm
coil or surrounding components such as electrical wiring,
painted metal surfaces, or insulation. Use of
non-- recommended coil cleaners is strongly discouraged
since coil and unit durability could be affected.

CAUTION

PERSONAL INJURY HAZARD
Failure to follow this caution may result in reduced
unit performance.
High velocity water from a pressure washer, garden
hose, or compressed air should never be used to clean
a coil. The force of the wter or air jet will bend the fin
edges and icrease airside pressure drop.

CAUTION

PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal
injury or equipment damage.
Chemical cleaning should NOT be used on the
aluminum NOVATION condenser. Damage to the coil
may occur. Only approved cleaning is recommended.

CAUTION

Totaline Environmentally Sound Coil Cleaner application
Instructions
1. Proper eye protection such as safety glasses is recommended during mixing and application.
2. Remove all surface loaded fibers and dirt with a vacuum cleaner as described above.
3. Thoroughly wet finned surfaces with clean water and
a low velocity garden hose, being carefull not to bend
fins.
4. Mix Totaline environmentally sound coil cleaner in a
2 1/2 gallon garden spryer according to the instructions included with the cleaner. The optimum solution
temperature is 100°F (38°C).
NOTE: Do NOT USE water in excess of 130°F (54°C),
as the enzymatic activity will be destroyed.
1. Thoroughly apply Totaline® environmentally sound
coil cleaner solution to all coil surfaces including
finned area, tube sheets and coil headers.
2. Hold garden sprayer nozzle close to finned areas and
apply cleaner with a vertical, up-- and-- down motion.
Avoid spraying in horizontal pattern to minimize potential for fin damage.
3. Ensure cleaner thoroughly penetrates deep into finned
areas.
4. Interior and exterior finned areas must be thoroughly
cleaned.

7

48TC

!

48TC

5. Finned surfaces should remain wet with cleaning
solution for 10 minutes.
6. Ensure surfaces are not allowed to dry before rinsing.
Reapply cleaner as needed to ensure 10-- minute saturation is achieved.
7. Thoroghly rinse all surfaces with low velocity clean
water using downward rinsing motion of water spray
nozzle. Protect fins from damage from the spray
nozzle.
Evaporator Coil Metering Devices

Because Puron (R-- 410A) refrigerant is a blend, it is
strongly recommended that refrigerant always be removed
from the cylinder as a liquid. Admit liquid refrigerant into
the system in the discharge line. If adding refrigerant into
the suction line, use a commercial metering/expansion
device at the gauge manifold; remove liquid from the
cylinder, pass it through the metering device at the gauge
set and then pass it into the suction line as a vapor. Do not
remove Puron (R-- 410A) refrigerant from the cylinder as a
vapor.

The metering devices are multiple fixed-- bore devices
(Acutrolt) swaged into the horizontal outlet tubes from
the liquid header, located at the entrance to each
evaporator coil circuit path. These are non-- adjustable.
Service requires replacing the entire liquid header
assembly.

Amount of refrigerant charge is listed on the unit’s
nameplate. Refer to Carrier GTAC2-- 5 Charging,
Recovery, Recycling and Reclamation training manual
and the following procedures.

To check for possible blockage of one or more of these
metering devices, disconnect the supply fan contactor
(IFC) coil, then start the compressor and observe the
frosting pattern on the face of the evaporator coil. A frost
pattern should develop uniformly across the face of the
coil starting at each horizontal header tube. Failure to
develop frost at an outlet tube can indicate a plugged or a
missing orifice.

Refrigerant System Pressure Access Ports
There are two access ports in the system - on the suction
tube near the compressor and on the discharge tube near
the compressor. These are brass fittings with black plastic
caps. The hose connection fittings are standard 1/4 SAE
male flare couplings.
The brass fittings are two-- piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
spring-closed check valve core screwed into the base. (See
Fig. 9.) This check valve is permanently assembled into
this core body and cannot be serviced separately; replace
the entire core body if necessary. Service tools are
available from RCD that allow the replacement of the
check valve core without having to recover the entire
system refrigerant charge. Apply compressor refrigerant
oil to the check valve core’s bottom O-ring. Install the
fitting body with 96 +/-- 10 in-lbs of torque; do not
overtighten.

PURONR (R--410A) REFRIGERANT
This unit is designed for use with Puron (R-- 410A)
refrigerant. Do not use any other refrigerant in this
system.
Puron (R-- 410A) refrigerant is provided in pink (rose)
colored cylinders. These cylinders are available with and
without dip tubes; cylinders with dip tubes will have a
label indicating this feature. For a cylinder with a dip
tube, place the cylinder in the upright position (access
valve at the top) when removing liquid refrigerant for
charging. For a cylinder without a dip tube, invert the
cylinder (access valve on the bottom) when removing
liquid refrigerant.

Refrigerant Charge

Unit panels must be in place when unit is operating during
the charging procedure. To prepare the unit for charge
adjustment.
No Charge
Use standard evacuating techniques. After evacuating
system, weigh in the specified amount of refrigerant.
Low-- Charge Cooling
Using Cooling Charging Charts (Figs. 10, 11, 12, and 13),
vary refrigerant until the conditions of the appropriate
chart are met. Note the charging charts are different from
the type normally used. Charts are based on charging the
units to the correct superheat for the various operating
conditions. Accurate pressure gauge and temperature
sensing device are required. Connect the pressure gauge to
the service port on the suction line. Mount the temperature
sensing device on the suction line and insulate it so that
outdoor ambient temperature does not affect the reading.
Indoor-- air cfm must be within the normal operating range
of the unit.
To Use Cooling Charging Charts
Select the appropriate unit charging chart from Figs. 10,
11, 12, and 13.
S Sizes D08 and D12 each have one cooling charging chart
S Size D14 has two cooling charging charts: Circuit A and
Circuit B
Take the outdoor ambient temperature and read the
suction pressure gauge. Refer to chart to determine what
suction temperature should be. If suction temperature is
high, add refrigerant. If suction temperature is low,
carefully recover some of the charge. Recheck the suction
pressure as charge is adjusted.
For D14 size, perform this procedure once for Circuit A
(using the Circuit A chart) and once for Circuit B (using
the Circuit B chart).

8

SEAT

CORE

(Part No. EC39EZ067)
1/2-20 UNF RH
0.596

45

o

o

WASHER
O-RING

5/8” HEX

.47

1/2" HEX

This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.

Fig. 9 - CoreMax Access Port Assembly
EXAMPLE:
Model 48TC*D14
Circuit A:
Outdoor Temperature . . . . . . . . . . . . . . . . . . 85_F (29_C)
Suction Pressure . . . . . . . . . . . . . . . . . 125 psig (860 kPa)
Suction Temperature should be . . . . . . . . . . 58_F (14_C)
Circuit B:
Outdoor Temperature . . . . . . . . . . . . . . . . . . 85_F (29_C)
Suction Pressure . . . . . . . . . . . . . . . . . 120 psig (830 kPa)
Suction Temperature should be . . . . . . . . . . 60_F (16_C)

9

DEPRESSOR PER ARI 720
+.01/-.035
FROM FACE OF BODY
7/16-20 UNF RH

C08453

48TC

30

48TC

COOLING CHARGING CHARTS

Fig. 10 - Cooling Charging Charts (D08)

10

C08669

48TC

COOLING CHARGING CHARTS

Fig. 11 - Cooling Charging Charts (D12)

11

C08670

48TC

COOLING CHARGING CHARTS

Fig. 12 - Cooling Charging Charts (D14 - Circuit A)

12

C09151

48TC

COOLING CHARGING CHARTS

Fig. 13 - Cooling Charging Charts (D14 - Circuit B)

13

C09152

Table 1 – Cooling Service Analysis
PROBLEM

Compressor and Condenser
Fan Will Not Start.

Compressor Will Not Start But
Condenser Fan Runs.

CAUSE
Power failure.
Fuse blown or circuit breaker tripped.
Defective thermostat, contactor, transformer,
or control relay.
Insufficient line voltage.
Incorrect or faulty wiring.
Thermostat setting too high.
Faulty wiring or loose connections in
compressor circuit.
Compressor motor burned out, seized, or
internal overload open.
Defective run/start capacitor, overload, start
relay.

48TC

One leg of three--- phase power dead.
Refrigerant overcharge or undercharge.

Compressor Cycles (other
than normally satisfying
thermostat).

Compressor Operates
Continuously.

Excessive Head Pressure.

Head Pressure Too Low.

Excessive Suction Pressure.

Suction Pressure Too Low.

Evaporator Fan Will Not Shut
Off.
Compressor Makes Excessive
Noise.

Defective compressor.
Insufficient line voltage.
Blocked condenser.
Defective run/start capacitor, overload, or start
relay.
Defective thermostat.
Faulty condenser--- fan motor or capacitor.
Restriction in refrigerant system.
Dirty air filter.
Unit undersized for load.
Thermostat set too low.
Low refrigerant charge.
Leaking valves in compressor.
Air in system.
Condenser coil dirty or restricted.
Dirty air filter.
Dirty condenser coil.
Refrigerant overcharged.
Air in system.
Condenser air restricted or air short--- cycling.
Low refrigerant charge.
Compressor valves leaking.
Restriction in liquid tube.
High head load.
Compressor valves leaking.
Refrigerant overcharged.
Dirty air filter.
Low refrigerant charge.
Metering device or low side restricted.

REMEDY
Call power company.
Replace fuse or reset circuit breaker.
Replace component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
Check wiring and repair or replace.
Determine cause. Replace compressor.
Determine cause and replace.
Replace fuse or reset circuit breaker. Determine
cause.
Recover refrigerant, evacuate system, and recharge
to nameplate.
Replace and determine cause.
Determine cause and correct.
Determine cause and correct.
Determine cause and replace.

Temperature too low in conditioned area.
Outdoor ambient below 25° F.

Replace thermostat.
Replace.
Locate restriction and remove.
Replace filter.
Decrease load or increase unit size.
Reset thermostat.
Locate leak; repair and recharge.
Replace compressor.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
Replace filter.
Clean coil.
Recover excess refrigerant.
Recover refrigerant, evacuate system, and recharge.
Determine cause and correct.
Check for leaks; repair and recharge.
Replace compressor.
Remove restriction.
Check for source and eliminate.
Replace compressor.
Recover excess refrigerant.
Replace filter.
Check for leaks; repair and recharge.
Remove source of restriction.
Increase air quantity. Check filter and replace if
necessary.
Reset thermostat.
Install low--- ambient kit.

Time off delay not finished.

Wait for 30--- second off delay.

Compressor rotating in wrong direction.

Reverse the 3--- phase power leads.

Insufficient evaporator airflow.

14

Compressors

6. Reverse any two of the unit power leads.
7. Reapply power to the compressor.

Lubrication

!

CAUTION

UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to
components.
The compressor is in a PuronR refrigerant system and
uses a polyolester (POE) oil. This oil is extremely
hygroscopic, meaning it absorbs water readily. POE
oils can absorb 15 times as much water as other oils
designed for HCFC and CFC refrigerants. Avoid
exposure of the oil to the atmosphere.

!

The suction and discharge pressure levels should now
move to their normal start-- up levels.
NOTE: When the compressor is rotating in the wrong
direction, the unit makes an elevated level of noise and
does not provide cooling.

Filter Drier
Replace whenever refrigerant system is exposed to
atmosphere. Only use factory specified liquid-- line filter
driers with working pressures no less than 650 psig. Do
not install a suction-- line filter drier in liquid line. A
liquid-- line filter drier designed for use with Puron
refrigerant is required on every unit.

Condenser--Fan Adjustment (D08--D12 size)
1. Shut off unit power supply. Install lockout tag.
2. Remove condenser-fan assembly (grille, motor, and
fan).
3. Loosen fan hub setscrews.
4. Adjust fan height as shown in Fig. 14.
5. Tighten setscrews to 84 in-lbs (9.5 N-m).
6. Replace condenser-fan assembly.

WARNING

PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could result in personal
injury or death.
Relieve pressure and recover all refrigerant before
system repair or final unit disposal.
Wear safety glasses and gloves when handling
refrigerants.
Keep torches and other ignition sources away from
refrigerants and oils.

CONDUIT

0.14 in +0.0/-0.03
C08448

Fig. 14 - Condenser Fan Adjustment (D08-- D12)

Replacing Compressor
The compressor used with Puron refrigerant contains a
POE oil. This oil has a high affinity for moisture. Do not
remove the compressor’s tube plugs until ready to insert
the unit suction and discharge tube ends.

Condenser--Fan Adjustment (D14 size)
1.
2.
3.
4.
5.
6.

Compressor mounting bolt torque is 65-- 75 in-lbs
(7.3-- 8.5 N-m).
Compressor Rotation

Shut off unit power supply. Install lockout tag.
Remove condenser fan grille.
Loosen fan hub setscrews.
Adjust fan height as shown in Fig. 15.
Tighten setscrews to 84 in-lbs (9.5 N-m).
Replace fan grille.

On 3-phase units with scroll compressors, it is important
to be certain compressor is rotating in the proper
direction. To determine whether or not compressor is
rotating in the proper direction:
1. Connect service gauges to suction and discharge pressure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start-- up.
NOTE: If the suction pressure does not drop and the
discharge pressure does not rise to normal levels:
4. Note that the evaporator fan is probably also rotating
in the wrong direction.
5. Turn off power to the unit.

Fig. 15 - Condenser Fan Adjustment (D14)

C09094

Troubleshooting Cooling System
Refer to Table 1 for additional troubleshooting topics.
15

48TC

Compressors are charged with the correct amount of oil at
the factory.

CONVENIENCE OUTLETS

!

WARNING

48TC

ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Units with convenience outlet circuits may use
multiple disconnects. Check convenience outlet for
power status before opening unit for service. Locate
its disconnect switch, if appropriate, and open it.
Tag-- out this switch, if necessary.

The primary leads to the convenience outlet transformer
are not factory-- connected. Selection of primary power
source is a customer-- option. If local codes permit, the
transformer primary leads can be connected at the
line-- side terminals on a unit-- mounted non-- fused
disconnect or circuit-- breaker switch; this will provide
service power to the unit when the unit disconnect switch
or circuit-- breaker is open. Other connection methods will
result in the convenience outlet circuit being de-- energized
when the unit disconnect or circuit-- breaker is open. (See
Fig. 17.)

Two types of convenience outlets are offered on 48TC
models: Non-- powered and unit-- powered. Both types
provide a 125-volt GFCI (ground-- fault circuit-- interrupter)
duplex receptacle rated at 15-A behind a hinged
waterproof access cover, located on the end panel of the
unit. (See Fig. 16.)
Pwd-CO Transformer
Conv Outlet
GFCI
Pwd-CO
Fuse
Switch

CO8283

Fig. 17 - Powered Convenience Outlet Wiring

Fig. 16 - Convenience Outlet Location

C08128

UNIT
VOLTAGE
208,
230

CONNECT
AS

460

480

575

600

Non--Powered Type
This type requires the field installation of a
general-- purpose 125-- volt 15-- A circuit powered from a
source elsewhere in the building. Observe national and
local codes when selecting wire size, fuse or breaker
requirements and disconnect switch size and location.
Route 125-- v power supply conductors into the bottom of
the utility box containing the duplex receptacle.

Unit--Powered Type
A unit-- mounted transformer is factory-- installed to
stepdown the main power supply voltage to the unit to
115-- v at the duplex receptacle. This option also includes a
manual switch with fuse, located in a utility box and
mounted on a bracket behind the convenience outlet;
access is through the unit’s control box access panel. (See
Fig. 16.)

240

PRIMARY
CONNECTIONS
L1: RED +YEL
L2: BLU + GRA
L1: RED
Splice BLU + YEL
L2: GRA
L1: RED
L2: GRA

TRANSFORMER
TERMINALS
H1 + H3
H2 + H4
H1
H2 + H3
H4
H1
H2

Duty Cycle
The unit-- powered convenience outlet has a duty cycle
limitation. The transformer is intended to provide power
on an intermittent basis for service tools, lamps, etc; it is
not intended to provide 15-- amps loading for continuous
duty loads (such as electric heaters for overnight use).
Observe a 50% limit on circuit loading above 8-- amps
(i.e., limit loads exceeding 8-- amps to 30 minutes of
operation every hour).

16

Maintenance
Periodically test the GFCI receptacle by pressing the
TEST button on the face of the receptacle. This should
cause the internal circuit of the receptacle to trip and open
the receptacle. Check for proper grounding wires and
power line phasing if the GFCI receptacle does not trip as
required. Press the RESET button to clear the tripped
condition.

Duct smoke sensor
controller

Conduit nuts
(supplied by installer)

Fuse On Powered Type
The factory fuse is a Bussman “Fusetron” T-- 15,
non-- renewable screw-- in (Edison base) type plug fuse.

Conduit support plate
Terminal block cover
Controller housing
and electronics

Using Unit--Mounted Convenience Outlets

The smoke detector system consists of a four-- wire
controller and one or two sensors. Its primary function is
to shut down the rooftop unit in order to prevent smoke
from circulating throughout the building. It is not to be
used as a life saving device.

Controller
The controller (see Fig. 18) includes a controller housing,
a printed circuit board, and a clear plastic cover. The
controller can be connected to one or two compatible duct
smoke sensors. The clear plastic cover is secured to the
housing with a single captive screw for easy access to the
wiring terminals. The controller has three LEDs (for
Power, Trouble and Alarm) and a manual test/reset button
(on the cover face).

48TC

Fastener
(2X)

Trouble
Alarm

SMOKE DETECTORS

System

Controller cover

Conduit couplings
(supplied by installer)

Units with unit-- mounted convenience outlet circuits will
often require that two disconnects be opened to
de-- energize all power to the unit. Treat all units as
electrically energized until the convenience outlet power
is also checked and de-- energization is confirmed. Observe
National Electrical Code Article 210, Branch Circuits, for
use of convenience outlets.

Smoke detectors are available as factory-- installed options
on 48TC models. Smoke detectors may be specified for
Supply Air only or for Return Air without or with
economizer or in combination of Supply Air and Return
Air. Return Air smoke detectors are arranged for vertical
return configurations only. All components necessary for
operation are factory-- provided and mounted. The unit is
factory-- configured for immediate smoke detector
shutdown operation; additional wiring or modifications to
unit terminal board may be necessary to complete the unit
and smoke detector configuration to meet project
requirements.

Cover gasket
(ordering option)

Power

Test/reset
switch

Fig. 18 - Controller Assembly

C08208

Sensor
The sensor (see Fig. 19) includes a plastic housing, a
printed circuit board, a clear plastic cover, a sampling
tube inlet and an exhaust tube. The sampling tube (when
used) and exhaust tube are attached during installation.
The sampling tube varies in length depending on the size
of the rooftop unit. The clear plastic cover permits visual
inspections without having to disassemble the sensor. The
cover attaches to the sensor housing using four captive
screws and forms an airtight chamber around the sensing
electronics. Each sensor includes a harness with an RJ45
terminal for connecting to the controller. Each sensor has
four LEDs (for Power, Trouble, Alarm and Dirty) and a
manual test/reset button (on the left-- side of the housing).
Air is introduced to the duct smoke detector sensor’s
sensing chamber through a sampling tube that extends into
the HVAC duct and is directed back into the ventilation
system through a (shorter) exhaust tube. The difference in
air pressure between the two tubes pulls the sampled air
through the sensing chamber. When a sufficient amount of
smoke is detected in the sensing chamber, the sensor
signals an alarm state and the controller automatically
takes the appropriate action to shut down fans and
blowers, change over air handling systems, notify the fire
alarm control panel, etc.

17

The sensor uses a process called differential sensing to
prevent gradual environmental changes from triggering
false alarms. A rapid change in environmental conditions,
such as smoke from a fire, causes the sensor to signal an
alarm state but dust and debris accumulated over time
does not.

Smoke Detector Sensor

Duct smoke sensor

C08245

Exhaust tube

Fig. 20 - Typical Supply Air Smoke Detector Sensor
Location

Exhaust gasket

48TC

Sensor housing
and electronics
See
Detail A

Intake
gasket

Cover gasket
(ordering option)

TSD-CO2
(ordering option)

Sensor cover

Plug
Sampling tube
(ordered separately)

Coupling
Detail A

Return Air without Economizer — The sampling tube is
located across the return air opening on the unit basepan.
(See Fig. 21.) The holes in the sampling tube face
downward, into the return air stream. The sampling tube is
connected via tubing to the return air sensor that is
mounted on a bracket high on the partition between return
filter and controller location. (This sensor is shipped in a
flat-- mounting location. Installation requires that this
sensor be relocated to its operating location and the tubing
to the sampling tube be connected. See installation steps
below.)
Return Air Detector module
(shipping position shown)*

Magnetic
test/reset
switch

Controller module
Alarm
Trouble

Power
Dirty

Fig. 19 - Smoke Detector Sensor

C08209

For installations using two sensors, the duct smoke
detector does not differentiate which sensor signals an
alarm or trouble condition.

Smoke Detector Locations
Supply Air — The Supply Air smoke detector sensor is
located to the left of the unit’s indoor (supply) fan. (See
Fig. 20.) Access is through the fan access panel. There is
no sampling tube used at this location. The sampling tube
inlet extends through the side plate of the fan housing
(into a high pressure area). The controller is located on a
bracket to the right of the return filter, accessed through
the lift-- off filter panel.

Return Air Detector Sampling Tube
*RA detector must be moved from shipping position to operating position by installer

C07307

Fig. 21 - Typical Return Air Detector Location

Return Air with Economizer — The sampling tube is
inserted through the side plates of the economizer
housing, placing it across the return air opening on the
unit basepan. (See Fig. 22.) The holes in the sampling
tube face downward, into the return air stream. The
sampling tube is connected via tubing to the return air
sensor that is mounted on a bracket high on the partition
between return filter and controller location. (This sensor
is shipped in a flat-- mounting location. Installation
requires that this sensor be relocated to its operating
location and the tubing to the sampling tube be connected.
See installation steps below.)

18

4. Screw the sensor and detector plate into its operating
position using screws from Step 1. Make sure the
sampling tube connection is on the bottom and the exhaust tube is on the top. (See Fig. 23.)
5. Connect the flexible tube on the sampling inlet to the
sampling tube on the basepan.
6. For units with an economizer, the sampling tube is integrated into the economizer housing but the connection of the flexible tubing to the sampling tube is the
same.

Return Air
Sampling Tube

C08129

Fig. 22 - Return Air Sampling Tube Location

48TC

Completing Installation of Return Air Smoke
Sensor:

SCREWS
C08127

Fig. 24 - Return Air Sensor Operating Position
EXHAUST
TUBE
FLEXIBLE
EXTENSION
TUBE
SAMPLING

C08126

Fig. 23 - Return Air Detector Shipping Position

1. Unscrew the two screws holding the Return Air
Sensor detector plate. (See Fig. 23.) Save the screws.
2. Remove the Return Air Sensor and its detector plate.
3. Rotate the detector plate so the sensor is facing outwards and the sampling tube connection is on the bottom. (See Fig. 24.)

FIOP Smoke Detector Wiring and Response
All units: FIOP smoke detector is configured to
automatically shut down all unit operations when smoke
condition is detected. See Fig. 25, Smoke Detector
Wiring.
Highlight A: JMP 3 is factory-- cut, transferring unit
control to smoke detector.
Highlight B: Smoke detector NC contact set will open on
smoke alarm condition, de-- energizing the ORN
conductor.

19

B
D

C

F

48TC

E

A

Fig. 25 - Typical Smoke Detector System Wiring
Highlight C: 24-- v power signal via ORN lead is removed
at Smoke Detector input on LCTB; all unit operations
cease immediately.
PremierLinkt and RTU-- MP Controls: Unit operating
functions (fan, cooling and heating) are terminated as
described above. In addition:

Sensor and Controller Tests
Sensor Alarm Test
The sensor alarm test checks a sensor’s ability to signal an
alarm state. This test requires that you use a field provided
SD-- MAG test magnet.

!

Highlight D: On smoke alarm condition, the smoke
detector NO Alarm contact will close, supplying 24-- v
power to GRA conductor.

PremierLink: This signal is conveyed to PremierLink
FIOP’s TB1 at terminal TB1-- 6 (BLU lead). This signal
initiates the FSD sequence by the PremierLink control.
FSD status is reported to connected CCN network.

Using Remote Logic: Five conductors are provided for
field use (see Highlight F) for additional annunciation
functions.
Additional Application Data — Refer to Catalog No.
HKRNKA-- 1XA for discussions on additional control
features of these smoke detectors including multiple unit
coordination. (See Fig. 25.)

CAUTION

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
This test places the duct detector into the alarm state.
Unless part of the test, disconnect all auxiliary
equipment from the controller before performing the
test. If the duct detector is connected to a fire alarm
system, notify the proper authorities before
performing the test.

Highlight E: GRA lead at Smoke Alarm input on LCTB
provides 24-- v signal to FIOP DDC control.

RTU-- MP: The 24-- v signal is conveyed to RTU-- MP’s
J1-- 10 input terminal. This signal initiates the FSD
sequence by the RTU-- MP control. FSD status is reported
to connected BAS network.

C08246

Sensor Alarm Test Procedure
1. Hold the test magnet where indicated on the side of
the sensor housing for seven seconds.
2. Verify that the sensor’s Alarm LED turns on.
3. Reset the sensor by holding the test magnet against
the sensor housing for two seconds.
4. Verify that the sensor’s Alarm LED turns off.
Controller Alarm Test
The controller alarm test checks the controller’s ability to
initiate and indicate an alarm state.

20

Table 2 – Dirty LED Test

CAUTION

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
This test places the duct detector into the alarm state.
Disconnect all auxiliary equipment from the controller
before performing the test. If the duct detector is
connected to a fire alarm system, notify the proper
authorities before performing the test.
Controller Alarm Test Procedure
1. Press the controller’s test/reset switch for seven
seconds.
2. Verify that the controller’s Alarm LED turns on.
3. Reset the sensor by pressing the test/reset switch for
two seconds.
4. Verify that the controller’s Alarm LED turns off.
Dirty Controller Test

CAUTION

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Pressing the controller’s test/reset switch for longer
than seven seconds will put the duct detector into the
alarm state and activate all automatic alarm responses.
Dirty Controller Test Procedure
S Press the controller’s test/reset switch for two seconds.
S Verify that the controller’s Trouble LED flashes.
Dirty Sensor Test
The dirty sensor test provides an indication of the sensor’s
ability to compensate for gradual environmental changes.
A sensor that can no longer compensate for environmental
changes is considered 100% dirty and requires cleaning or
replacing. You must use a field provided SD-- MAG test
magnet to initiate a sensor dirty test. The sensor’s Dirty
LED indicates the results of the dirty test as shown in
Table 2.

!

CAUTION

DESCRIPTION

1

0--- 25% dirty. (Typical of a newly installed detector)

2

25--- 50% dirty

3

51--- 75% dirty

4

76--- 99% dirty

Dirty Sensor Test Procedure
1. Hold the test magnet where indicated on the side of
the sensor housing for two seconds.
2. Verify that the sensor’s Dirty LED flashes.

!

CAUTION

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Changing the dirty sensor test operation will put the
detector into the alarm state and activate all automatic
alarm responses. Before changing dirty sensor test
operation, disconnect all auxiliary equipment from the
controller and notify the proper authorities if
connected to a fire alarm system.

The dirty controller test checks the controller’s ability to
initiate a dirty sensor test and indicate its results.

!

FLASHES

Changing the Dirty Sensor Test
By default, sensor dirty test results are indicated by:
S The sensor’s Dirty LED flashing.
S The controller’s Trouble LED flashing.
S The controller’s supervision relay contacts toggle.
The operation of a sensor’s dirty test can be changed so
that the controller’s supervision relay is not used to
indicate test results. When two detectors are connected to
a controller, sensor dirty test operation on both sensors
must be configured to operate in the same manner.
To Configure the Dirty Sensor Test Operation
1. Hold the test magnet where indicated on the side of
the sensor housing until the sensor’s Alarm LED turns
on and its Dirty LED flashes twice (approximately 60
seconds).
2. Reset the sensor by removing the test magnet then
holding it against the sensor housing again until the
sensor’s Alarm LED turns off (approximately 2
seconds).
Remote Station Test
The remote station alarm test checks a test/reset station’s
ability to initiate and indicate an alarm state.

!

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Holding the test magnet against the sensor housing for
more than seven seconds will put the duct detector
into the alarm state and activate all automatic alarm
responses.

CAUTION

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
This test places the duct detector into the alarm state.
Unless part of the test, disconnect all auxiliary
equipment from the controller before performing the
test. If the duct detector is connected to a fire alarm
system, notify the proper authorities before
performing the test.
21

48TC

!

48TC

SD-- TRK4 Remote Alarm Test Procedure
1. Turn the key switch to the RESET/TEST position for
seven seconds.
2. Verify that the test/reset station’s Alarm LED turns
on.
3. Reset the sensor by turning the key switch to the
RESET/TEST position for two seconds.
4. Verify that the test/reset station’s Alarm LED turns
off.
Remote Test/Reset Station Dirty Sensor Test
The test/reset station dirty sensor test checks the test/reset
station’s ability to initiate a sensor dirty test and indicate
the results. It must be wired to the controller as shown in
Fig. 26 and configured to operate the controller’s
supervision relay. For more information, see “Changing
the Dirty Sensor Test.”

Dirty Sensor Test Using an SD-- TRK4
1. Turn the key switch to the RESET/TEST position for
two seconds.
2. Verify that the test/reset station’s Trouble LED
flashes.

Detector Cleaning
Cleaning the Smoke Detector
Clean the duct smoke sensor when the Dirty LED is
flashing continuously or sooner if conditions warrant.

!

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
If the smoke detector is connected to a fire alarm
system, first notify the proper authorities that the
detector is undergoing maintenance then disable the
relevant circuit to avoid generating a false alarm.

12
Smoke Detector Controller

1
TB3

3

1

−

2

+

CAUTION

1. Disconnect power from the duct detector then remove
the sensor’s cover. (See Fig. 27.)

Auxiliary
equipment

14

Sampling
tube

SD-TRK4

Supervision relay
contacts [3]

Trouble
13

19
Wire must be
added by installer

5
18 Vdc ( +)

HVAC duct
Sensor
housing

Power
4
Alarm

Optic
plate

Airflow

15

1

2

3

Retainer
clip

2

Optic
housing

Reset/Test

20

18 Vdc ( −)

C08247

Fig. 26 - Remote Test/Reset Station Connections

!

Fig. 27 - Sensor Cleaning Diagram

CAUTION

2. Using a vacuum cleaner, clean compressed air, or a
soft bristle brush, remove loose dirt and debris from
inside the sensor housing and cover.
Use isopropyl alcohol and a lint-- free cloth to remove
dirt and other contaminants from the gasket on the
sensor’s cover.
3. Squeeze the retainer clips on both sides of the optic
housing then lift the housing away from the printed
circuit board.
4. Gently remove dirt and debris from around the optic
plate and inside the optic housing.
5. Replace the optic housing and sensor cover.
6. Connect power to the duct detector then perform a
sensor alarm test.

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
If the test/reset station’s key switch is left in the
RESET/TEST position for longer than seven seconds,
the detector will automatically go into the alarm state
and activate all automatic alarm responses.

!

C07305

CAUTION

OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Holding the test magnet to the target area for longer
than seven seconds will put the detector into the alarm
state and activate all automatic alarm responses.

22

Normal State
The smoke detector operates in the normal state in the
absence of any trouble conditions and when its sensing
chamber is free of smoke. In the normal state, the Power
LED on both the sensor and the controller are on and all
other LEDs are off.
Alarm State
The smoke detector enters the alarm state when the
amount of smoke particulate in the sensor’s sensing
chamber exceeds the alarm threshold value. (See Table 3.)
Upon entering the alarm state:
S The sensor’s Alarm LED and the controller’s Alarm LED
turn on.
S The contacts on the controller’s two auxiliary relays
switch positions.
S The contacts on the controller’s alarm initiation relay
close.
S The controller’s remote alarm LED output is activated
(turned on).
S The controller’s high impedance multiple fan shutdown
control line is pulled to ground Trouble state.
The SuperDuct duct smoke detector enters the trouble
state under the following conditions:
S A sensor’s cover is removed and 20 minutes pass before
it is properly secured.
S A sensor’s environmental compensation limit is reached
(100% dirty).
S A wiring fault between a sensor and the controller is
detected.
An internal sensor fault is detected upon entering the
trouble state:
S The contacts on the controller’s supervisory relay switch
positions. (See Fig. 28.)
S If a sensor trouble, the sensor’s Trouble LED the
controller’s Trouble LED turn on.
S If 100% dirty, the sensor’s Dirty LED turns on and the
controller’s Trouble LED flashes continuously.
S If a wiring fault between a sensor and the controller, the
controller’s Trouble LED turns on but not the sensor’s.
Trouble
Alarm

Power

NOTE: All troubles are latched by the duct smoke
detector. The trouble condition must be cleared and then
the duct smoke detector must be reset in order to restore it
to the normal state.
Resetting Alarm and Trouble Condition Trips:
Manual reset is required to restore smoke detector systems
to Normal operation. For installations using two sensors,
the duct smoke detector does not differentiate which
sensor signals an alarm or trouble condition. Check each
sensor for Alarm or Trouble status (indicated by LED).
Clear the condition that has generated the trip at this
sensor. Then reset the sensor by pressing and holding the
reset button (on the side) for 2 seconds. Verify that the
sensor’s Alarm and Trouble LEDs are now off. At the
controller, clear its Alarm or Trouble state by pressing and
holding the manual reset button (on the front cover) for 2
seconds. Verify that the controller’s Alarm and Trouble
LEDs are now off. Replace all panels.

Troubleshooting
Controller’s Trouble LED is On
1. Check the Trouble LED on each sensor connected to
the controller. If a sensor’s Trouble LED is on, determine the cause and make the necessary repairs.
2. Check the wiring between the sensor and the controller. If wiring is loose or missing, repair or replace as
required.
Controller’s Trouble LED is Flashing
1. One or both of the sensors is 100% dirty.
2. Determine which Dirty LED is flashing then clean
that sensor assembly as described in the detector
cleaning section.
Sensor’s Trouble LED is On
1. Check the sensor’s Dirty LED. If it is flashing, the
sensor is dirty and must be cleaned.
2. Check the sensor’s cover. If it is loose or missing, secure the cover to the sensor housing.
3. Replace sensor assembly.
Sensor’s Power LED is Off
1. Check the controller’s Power LED. If it is off, determine why the controller does not have power and
make the necessary repairs.
2. Check the wiring between the sensor and the controller. If wiring is loose or missing, repair or replace as
required.

Test/reset
switch

Fig. 28 - Controller Assembly

C07298

23

48TC

INDICATORS

Table 3 – Detector Indicators
CONTROL OR INDICATOR
Magnetic test/reset switch
Alarm LED
Trouble LED
Dirty LED

48TC

Power LED

DESCRIPTION
Resets the sensor when it is in the alarm or trouble state. Activates or tests the sensor when it is in
the normal state.
Indicates the sensor is in the alarm state.
Indicates the sensor is in the trouble state.
Indicates the amount of environmental compensation used by the sensor
(flashing continuously = 100%)
Indicates the sensor is energized.

Controller’s Power LED is Off
1. Make sure the circuit supplying power to the controller is operational. If not, make sure JP2 and JP3 are
set correctly on the controller before applying power.
2. Verify that power is applied to the controller’s supply
input terminals. If power is not present, replace or repair wiring as required.
Remote Test/Reset Station’s Trouble LED Does Not
flash When Performing a Dirty Test, But the
Controller’s Trouble LED Does
1. Verify that the remote test/station is wired as shown
in Fig. 26. Repair or replace loose or missing wiring.
2. Configure the sensor dirty test to activate the controller’s supervision relay. See “Changing sensor dirty
test operation.”
Sensor’s Trouble LED is On, But the Controller’s
Trouble LED is OFF
Remove JP1 on the controller.

PROTECTIVE DEVICES
Compressor Protection
Overcurrent
Each compressor has internal linebreak motor protection.
Reset is automatic after compressor motor has cooled.
Overtemperature
Each compressor has an internal protector to protect it
against excessively high discharge gas temperatures. Reset
is automatic.
High Pressure Switch
Each system is provided with a high pressure switch
mounted on the discharge line. The switch is
stem-- mounted and brazed into the discharge tube. Trip
setting is 630 psig +/-- 10 psig (4344 +/-- 69 kPa) when
hot. Reset is automatic at 505 psig (3482 kPa).

2.9 and 3.7 bhp motors are equipped with an
overtemperature or protection device. The type of device
depends on the motor size. See Table 4.
The High Static option supply fan motor is equipped with
a pilot-- circuit Thermix combination overtemperature/
overcurrent protection device. This device resets
automatically. Do not bypass this switch to correct
trouble. Determine the cause and correct it.
The Thermik device is a snap-- action overtemperature
protection device that is imbedded in the motor windings.
It is a pilot-- circuit device that is wired into the unit’s 24-- v
control circuit. When this switch reaches its trip setpoint,
it opens the 24-- v control circuit and causes all unit
operation to cease. This device resets automatically when
the motor windings cool. Do not bypass this switch to
correct trouble. Determine the cause and correct it.
The
External
motor
overload
device
is a
specially-- calibrated circuit breaker that is UL recognized
as a motor overload controller. It is an overcurrent
device. When the motor current exceeds the circuit
breaker setpoint, the device opens all motor power leads
and the motor shuts down. Reset requires a manual reset
at the overload switch. This device (designated IFCB) is
located on the side of the supply fan housing, behind the
fan access panel.
Troubleshooting supply fan motor overload trips: The
supply fan used in 48TC units is a forward-- curved
centrifugal wheel. At a constant wheel speed, this wheel
has a characteristic that causes the fan shaft load to
DECREASE when the static pressure in the unit-- duct
system increases and to INCREASE when the static
pressure in the unit-- duct system decreases (and fan
airflow rate increases).
Motor overload conditions
typically develop when the unit is operated with an access
panel removed, with unfinished duct work, in an
economizer-- open mode, or a leak develops in the duct
system that allows a bypass back to unit return opening.

Low Pressure Switch
Each system is protected against a loss of charge and low
evaporator coil loading condition by a low pressure switch
located on the suction line near the compressor. The
switch is stem-- mounted. Trip setting is 54 psig +/-- 5 psig
(372 +/-- 34 kPa). Reset is automatic at 117 +/-- 5 psig
(807 +/-- 34 kPa).

Table 4 - Overcurrent Device Type
Motor Size (bhp)

Overload Device

Reset

1.7

Internal Linebreak

Automatic

2.4

Internal Linebreak

Automatic

2.9

Thermik

Automatic

3.7

Thermik

Automatic

4.7

External
(Circuit Breaker)

Manual

Supply (Indoor) Fan Motor Protection
Disconnect and lockout power when servicing fan motor.
24

Condenser Fan Motor Protection

Fuel Types and Pressures

The condenser fan motor is internally protected against
overtemperature.

Natural Gas — The 48TC unit is factory-- equipped for use
with Natural Gas fuel at elevation under 2000 ft (610 m).
See section Orifice Replacement for information in
modifying this unit for installation at elevations above
2000 ft (610 m).

Control Circuit, 24--V
The control circuit is protected against overcurrent
conditions by a circuit breaker mounted on control
transformer TRAN. Reset is manual.

GAS HEATING SYSTEM

Table 5 – Natural Gas Supply Line Pressure Ranges

The heat exchanger system consists of a gas valve feeding
multiple inshot burners off a manifold. The burners fire
into matching primary tubes. The primary tubes discharge
into combustion plenum where gas flow converges into
secondary tubes. The secondary tubes exit into the
induced draft fan wheel inlet. The induced fan wheel
discharges into a flue passage and flue gases exit out a
flue hood on the side of the unit. The induced draft fan
motor includes a Hall Effect sensor circuit that confirms
adequate wheel speed via the Integrated Gas Control
(IGC) board. Safety switches include a Rollout Switch (at
the top of the burner compartment) and a limit switch
(mounted through the fan deck, over the tubes). (See Fig.
29 and 30.)
INDUCEDDRAFT
MOTOR
MOUNTING
PLATE

ROLLOUT
SWITCH

BURNER
SECTION

FLUE
EXHAUST
VESTIBULE
PLATE

MANIFOLD
PRESSURE
TAP
GAS
VALVE

48TC

All

MIN
4.0 in. wg
(996 Pa)

MAX
13.0 in. wg
(3240 Pa)

Manifold pressure is factory-- adjusted for NG fuel use.
Adjust as required to obtain best flame characteristic.
Table 6 – Natural Gas Manifold Pressure Ranges
UNIT
MODEL

UNIT
SIZE

48TC

All

HIGH
FIRE
3.5 in. wg
(872 Pa)

LOW
FIRE
1.7 in. wg
(423 Pa)

RANGE
2.0--- 5.0 in. wg (Hi)
(498--- 1245 Pa)

Liquid Propane — Accessory packages are available for
field-- installation that will convert the 48TC unit to
operate with Liquid Propane (LP) fuels. These kits include
new orifice spuds, new springs for gas valves and a supply
line low pressure switch. See section on Orifice
Replacement for details on orifice size selections.
Fuel line pressure entering unit gas valve must remain
within specified range.
Table 7 – Liquid Propane Supply Line Pressure Ranges
UNIT MODEL

UNIT SIZE

48TC

All

C09153

Limit Switch
and Shield

Fig. 30 - Limit Switch Location

UNIT SIZE

MIN
11.0 in. wg
(2740 Pa)

MAX
13.0 in. wg
(3240 Pa)

Manifold pressure for LP fuel use must be adjusted to
specified range. Follow instructions in the accessory kit to
make initial readjustment.

BLOWER
HOUSING

Fig. 29 - Burner Section Details

UNIT MODEL

Table 8 – Liquid Propane Manifold Pressure Ranges
UNIT MODEL

UNIT SIZE

48TC

All

HIGH FIRE
10.0 in. wg
(2490 Pa)

LOW FIRE
5.0 in. wg
(1245 Pa)

Supply Pressure Switch — The LP conversion kit includes
a supply low pressure switch. The switch contacts (from
terminal C to terminal NO) will open the gas valve power
whenever the supply line pressure drops below the
setpoint. (See Fig. 31 and 32.) If the low pressure remains
open for 15 minutes during a call for heat, the IGC circuit
will initiate a Ignition Fault (5 flashes) lockout. Reset of
the low pressure switch is automatic on rise in supply line
pressure. Reset of the IGC requires a recycle of unit
power after the low pressure switch has closed.
C08284

25

48TC

General

INDUCEDDRAFT MOTOR

Gas line pressure entering the unit’s main gas valve must
be within specified ranges. Adjust unit gas regulator valve
as required or consult local gas utility.

This switch also prevents operation when the propane tank
level is low which can result in gas with a high
concentration of impurities, additives, and residues that
have settled to the bottom of the tank. Operation under
these conditions can cause harm to the heat exchanger
system. Contact your fuel supplier if this condition is
suspected.

Flue Gas Passageways
To inspect the flue collector box and upper areas of the
heat exchanger:

C08238

48TCDD08 only

48TC

1. Remove the combustion blower wheel and motor assembly according to directions in Combustion-- Air
Blower section. (See Fig. 33.)
2. Remove the flue cover to inspect the heat exchanger.
3. Clean all surfaces as required using a wire brush.

Combustion--Air Blower
Clean periodically to assure proper airflow and heating
efficiency. Inspect blower wheel every fall and
periodically during heating season. For the first heating
season, inspect blower wheel bi-- monthly to determine
proper cleaning frequency.
To access burner section, slide the sliding burner partition
out of the unit.
To inspect blower wheel, shine a flashlight into draft hood
opening. If cleaning is required, remove motor and wheel
as follows:
1. Slide burner access panel out.
2. Remove the 7 screws that attach induced-- draft motor
housing to vestibule plate. (See Fig. 33.)
3. The blower wheel can be cleaned at this point. If additional cleaning is required, continue with Steps 4
and 5.
4. To remove blower from the motor shaft, remove 2
setscrews.
5. To remove motor, remove the 4 screws that hold the
motor to mounting plate. Remove the motor cooling
fan by removing one setscrew. Then remove nuts that
hold motor to mounting plate.
6. To reinstall, reverse the procedure outlined above.

C08239

All 48TC*D except DD08
Fig. 31 - LP Low Pressure Switch (Installed)
LP LPS

IGC
BRN

C

NO

BRN

J2-11
MGV

IGC
GRA

J2-12
W2

TSTAT

C

PNK
C08285

Fig. 32 - LP Supply Line Low Pressure Switch Wiring

26

HEATER TUBE
ASSEMBLY
SEAL STRIPS,
SPONGE RUBBER
REGULATOR
GASKET
REGULATOR

RETAINER

48TC

WIND CAP
ASSEMBLY
(SHOWN
INVERTED,
AS SHIPPED)

SUPPORT INSULATION ASSEMBLY

INDUCER FAN-MOTOR ASSEMBLY

BURNER ASSEMBLY
C08227

Fig. 33 - Heat Exchanger Assembly

Burners and Igniters

!

ORIFICE

CAUTION

1.00-in
(25.4 mm)

EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in
equipment damage.
When working on gas train, do not hit or plug
orifice spuds.

MANIFOLD
PIPE

Fig. 34 - Orifice Projection

Main Burners
To access burners, remove burner access panel and slide
out burner partition. At the beginning of each heating
season, inspect for deterioration or blockage due to
corrosion or other causes. Observe the main burner flames
and adjust, if necessary.

C08211

Removal and Replacement of Gas Train
See Fig. 29, 33, and 35.
1.
2.
3.
4.
5.

Orifice projection — Refer to Fig. 34 for maximum
projection dimension for orifice face to manifold tube.

27

Shut off manual gas valve.
Shut off power to unit.
Slide out burner partition.
Disconnect gas piping at unit gas valve.
Remove wires connected to gas valve. Mark each
wire.

7. Reinstall burner rack as described in Removal and
Replacement of Gas Train section, above.

MANIFOLD PRESSURE TAP

Gas Valve — All unit sizes are equipped with 2-- stage gas
valves. See Fig. 38 for locations of adjustment screws and
features on the gas valves.
To adjust gas valve pressure settings:

GAS
VALVE

BURNERS

48TC

Fig. 35 - Burner Tray Details

C09154

6. Remove igniter wires and sensor wires at the Integrated Gas Unit Controller (IGC). (See Fig. 36.)
7. Remove the 2 screws that attach the burner rack to
the vestibule plate. (See Fig. 33.)
8. Slide the burner tray out of the unit. (See Fig. 35.)
9. To reinstall, reverse the procedure outlined above.
Cleaning and Adjustment
1. Remove burner rack from unit as described in Removal and Replacement of Gas Train section, above.
2. Inspect burners; if dirty, remove burners from rack.
(Mark each burner to identify its position before removing from the rack.)
3. Use a soft brush to clean burners and cross-- over port
as required.
4. Adjust spark gap. (See Fig. 37.)
5. If factory orifice has been removed, check that each
orifice is tight at its threads into the manifold pipe
and that orifice projection does not exceed maximum
valve. (See Fig. 34).
6. Reinstall burners on rack in the same locations as
factory-- installed. (The outside crossover flame regions of the outermost burners are pinched off to prevent excessive gas flow from the side of the burner
assembly. If the pinched crossovers are installed
between two burners, the flame will not ignite properly.)
RACEWAY

INTEGRATED GAS UNIT
CONTROLLER (IGC)

IMPORTANT: Leak check all gas connections including
the main service connection, gas valve, gas spuds, and
manifold pipe plug. All leaks must be repaired before
firing unit.
Check Unit Operation and Make Necessary
Adjustments
NOTE: Gas supply pressure at gas valve inlet must be
within specified ranges for fuel type and unit size. (See
Table 5, 6, 7, and 8.)
1. Remove manifold pressure tap plug from manifold
and connect pressure gauge or manometer. (See Fig.
35.)
2. Turn on electrical supply.
3. Turn on unit main gas valve.
4. Set room thermostat to call for heat. Verify high-stage heat operation before attempting to adjust manifold pressure.
5. When main burners ignite, check all fittings, manifold, and orifices for leaks.
6. Adjust high-- stage pressure to specified setting by
turning the plastic adjustment screw clockwise to increase pressure, counter-- clockwise to decrease pressure.
7. Set room thermostat to call for low-- stage heat. Adjust
low-- stage pressure to specified setting.
8. Replace regulator cover screw(s) when finished.
9. With burner access panel removed, observe unit heating operation in both high stage and low stage operation. Observe burner flames to see if they are blue in
appearance, and that the flames are approximately the
same for each burner.
10. Turn off unit, remove pressure manometer and replace the 1/8 in. pipe fitting on the gas manifold. (See
Fig. 35.)
Limit Switch
Remove blower access panel. Limit switch is located on
the fan deck. (See Fig. 30.)

HOLE IN END PANEL (HIDDEN)

Fig. 36 - Unit Control Box/IGC Location

C08454

28

125,000/90,000 BTUH INPUT

48TC

180,000/120,000 BTUH INPUT

240,000/180,000 BTUH INPUT
250,000/200,000 BTUH INPUT

C08447

Fig. 37 - Spark Adjustment (08-- 14)

Burner Ignition

Table 9 – LED Error Code Description*

Unit is equipped with a direct spark ignition 100% lockout
system. Integrated Gas Unit Controller (IGC) is located in
the control box. (See Fig. 36.) The IGC contains a
self-- diagnostic LED (light-- emitting diode). A single LED
(see Fig. 39) on the IGC provides a visual display of
operational or sequential problems when the power supply
is uninterrupted. When a break in power occurs, the IGC
will be reset (resulting in a loss of fault history) and the
indoor (evaporator) fan ON/OFF times will be reset. The
LED error code can be observed through the viewport.
During servicing refer to the label on the control box
cover or Table 9 for an explanation of LED error code
descriptions.
If lockout occurs, unit may be reset by interrupting power
supply to unit for at least 5 seconds.

LED INDICATION

ERROR CODE
DESCRIPTION

ON

Normal Operation

OFF

Hardware Failure

2 Flashes

Limit Switch Fault

3 Flashes

Flame Sense Fault

4 Flashes

4 Consecutive Limit Switch Faults

5 Flashes

Ignition Lockout Fault

6 Flashes

Induced --- Draft Motor Fault

7 Flashes

Rollout Switch Fault

8 Flashes

Internal Control Fault

9 Flashes

Software Lockout

LEGEND
LED --- Light Emitting Diode
* A 3 – second pause exists between LED error code flashes. If
more than one error code exists, all applicable codes will be
displayed in numerical sequence.

IMPORTANT: Refer to Troubleshooting Tables 13 and
14 for additional information.

29

C08240

48TC

48TCDD08 only

All 48TC*D except DD08

C08241

Fig. 38 - Gas Valve

Orifice Replacement
This unit uses orifice type LH32RFnnn (where nnn
indicates orifice reference size). When replacing unit
orifices, order the necessary parts via Carrier RCD. See
Table 11 for available orifice sizes. See Table 12 for
orifice sizes for Natural Gas and LP fuel usage at various
elevations above sea level.

Check that each replacement orifice is tight at its threads
into the manifold pipe and that orifice projection does not
exceed maximum value. (See Fig. 34.)

30

48TC

Red LED-Status

C08452

Fig. 39 - Integrated Gas Control (IGC) Board
Table 10 – IGC Connections
TERMINAL LABEL

POINT DESCRIPTION

SENSOR LOCATION

TYPE OF I/O

CONNECTION
PIN NUMBER

INPUTS
RT, C

Input power from TRAN 1

control box

24 VAC

SS

Speed sensor

gas section

analog input

FS, T1

Flame sensor

gas section

switch input

—
J1, 1-3
—

W

Heat stage 1

LCTB

24 VAC

J2, 2

RS

Rollout switch

gas section

switch input

J2, 5-6

LS

Limit switch

fan section

switch input

J2, 7-8

CS

Centrifugal switch (not used)

switch input

J2, 9-10

—

OUTPUTS
L1, CM

Induced draft combustion motor

gas section

line VAC

IFO

Indoor fan

control box

relay

J2, 1

GV

Gas valve (heat stage 1)

gas section

relay

J2, 11-12

31

48TC

Table 11 – Orifice Sizes
ORIFICE
DRILL SIZE
#30
1/8
#31
#32
#33
#34
#35
#36
#37
#38
#39
#40
#41
#42
#43
#44
#45
#46
#47
#48
#49
#50
#51
#52
#53
#54
#55
#56
#57
#58

CARRIER
PART NUMBER
LH32RF129
LH32RF125
LH32RF120
LH32RF116
LH32RF113
LH32RF111
LH32RF110
LH32RF105
LH32RF104
LH32RF102
LH32RF103
LH32RF098
LH32RF096
LH32RF094
LH32RF089
LH32RF086
LH32RF082
LH32RF080
LH32RF079
LH32RF076
LH32RF073
LH32RF070
LH32RF067
LH32RF065
LH32RF060
LH32RF055
LH32RF052
LH32RF047
LH32RF043
LH32RF042

DRILL
DIA. (in.)
0.1285
0.1250
0.1200
0.1160
0.1130
0.1110
0.1100
0.1065
0.1040
0.1015
0.0995
0.0980
0.0960
0.0935
0.0890
0.0860
0.0820
0.0810
0.0785
0.0760
0.0730
0.0700
0.0670
0.0635
0.0595
0.0550
0.0520
0.0465
0.0430
0.0420

Table 12 - Altitude Compensation* (08-- 14)
ELEVATION
ft (m)
0 --- 2000 (610)
2000 (610)
3000 (914)
4000 (1219)
5000 (1524)
6000 (1829)
7000 (2134)
8000 (2438)
9000 (2743)
10000 (3048)
11000 (3353)
12000 (3658)
13000 (3962)
14000 (4267)

125,000
BTUH Nominal
NG Orifice
LP Orifice
Size
Size
311
493
1
32
503
321
503
331
503
1
33
514
1
34
514
351
514
361
524
372
524
2
38
524
392
534
†41
534
†42
544
†43
544

250,000
BTUH Nominal
NG Orifice
LP Orifice
Size
Size
†30
463
†30
473
311
473
311
483
1
31
483
1
31
483
321
493
331
493
341
503
1
35
503
361
514
372
514
382
524
†40
534

LEGEND
NG = Natural Gas
LP = Liquid Propane
* As the height above sea level increases, there is less oxygen
per cubic ft. of air. Therefore, heat input rate should be reduced
at higher altitudes.
{ Not included in kit. May be purchased separately through
dealer.

1 = CRLPELEV001A00
2 = CRLPELEV002A00
3 = CRLPELEV003A00
4 = CRLPELEV004A00

32

180,000, 224,000
BTUH Nominal
NG Orifice
LP Orifice
Size
Size
311
483
1
32
493
321
493
331
493
1
33
503
1
34
503
351
503
361
514
372
514
2
38
524
392
524
†41
534
†42
534
†43
544

When operating on first stage heating, the minimum
temperature of air entering the dimpled heat exchanger is
50_F continuous and 45_F intermittent for standard heat
exchangers and 40_F continuous and 35_F intermittent for
stainless steel heat exchangers. To operate at lower
mixed-- air temperatures, a field-- supplied outdoor-- air
thermostat must be used to initiate both stages of heat
when the temperature is below the minimum required
temperature to ensure full fire operation. Wire the
outdoor-- air thermostat OALT (part no. HH22AG106) in
series with the second stage gas valve. See Fig. 40. Set the
outdoor-- air thermostat at 35_F for stainless steel heat
exchangers or 45_F for standard heat exchangers. This
temperature setting will bring on the second stage of heat
whenever the ambient temperature is below the thermostat
setpoint. Indoor comfort may be compromised when
heating is initiated using low entering air temperatures
with insufficient heating temperature rise.

Thermostat
TH1

LCTB
W1

W1
OALT

TH2
W2

Fig. 40 - OATL Connections

W2
C08442

Troubleshooting Heating System
Refer to Table 13 and 14 for additional troubleshooting
topics.
48TC

Minimum Heating Entering Air Temperature

Table 13 – Heating Service Analysis
PROBLEM

CAUSE
Misaligned spark electrodes.

No gas at main burners.

Burners Will Not Ignite.

Water in gas line.
No power to furnace.
No 24 v power supply to control
circuit.
Miswired or loose connections.
Burned ---out heat anticipator in
thermostat.
Broken thermostat wires.
Dirty air filter.
Gas input to unit too low.

Inadequate Heating.

Unit undersized for application.
Restricted airflow.
Blower speed too low.
Limit switch cycles main burners.
Too much outdoor air.

Poor Flame
Characteristics.

Incomplete combustion (lack of
combustion air) results in:
Aldehyde odors, CO, sooting
flame, or floating flame.

Burners Will Not Turn
Off.

Unit is locked into Heating mode
for a one minute minimum.

REMEDY
Check flame ignition and sensor electrode positioning.
Adjust as needed.
Check gas line for air, purge as necessary. After purging
gas line of air, allow gas to dissipate for at least 5 minutes
before attempting to relight unit.
Check gas valve.
Drain water and install drip leg to trap water.
Check power supply, fuses, wiring, and circuit breaker.
Check transformer. Transformers with internal overcurrent
protection require a cool down period before resetting.
Check all wiring and wire nut connections.
Replace thermostat.
Run continuity check. Replace wires, if necessary.
Clean or replace filter as necessary.
Check gas pressure at manifold. Clock gas meter for input.
If too low, increase manifold pressure, or replace with
correct orifices.
Replace with proper unit or add additional unit.
Clean filter, replace filter, or remove any restrictions.
Use high speed tap, increase fan speed, or install optional
blower, as suitable for individual units.
Check rotation of blower, thermostat heat anticipator
settings, and temperature rise of unit. Adjust as needed.
Adjust minimum position.
Check economizer operation.
Check all screws around flue outlets and burner
compartment. Tighten as necessary.
Cracked heat exchanger.
Overfired unit — reduce input, change orifices, or adjust
gas line or manifold pressure.
Check vent for restriction. Clean as necessary.
Check orifice to burner alignment.
Wait until mandatory one ---minute time period has elapsed
or reset power to unit.

33

Table 14 – IGC Board LED Alarm Codes
LED
FLASH
CODE
On

48TC

Off

DESCRIPTION
Normal Operation
Hardware Failure

ACTION TAKEN BY
CONTROL

RESET METHOD

—

—

No gas heating.

—

PROBABLE CAUSE
—
Loss of power to the IGC. Check 5 amp
fuse on IGC, power to unit, 24V circuit
breaker, transformer, and wiring to the
IGC.
High temperature limit switch is open.
Check the operation of the indoor
(evaporator) fan motor.
Ensure that the supply-air temperature
rise is within the range on the unit
nameplate. Check wiring and limit switch
operation.

2
Limit Switch Fault
Flashes

Gas valve and igniter
Off.
Limit switch closed,
Indoor fan and inducer or heat call (W) Off.
On.

3
Flame Sense Fault
Flashes

Flame sense normal. The IGC sensed a flame when the gas
Indoor fan and inducer
Power reset for LED valve should be closed. Check wiring,
On.
reset.
flame sensor, and gas valve operation.

4
Four Consecutive Limit
Flashes Switch Fault

No gas heating.

Heat call (W) Off.
Power reset for LED
reset.

4 consecutive limit switch faults within a
single call for heat. See Limit Switch Fault.

5
Ignition Fault
Flashes

No gas heating.

Heat call (W) Off.
Power reset for LED
reset.

Unit unsuccessfully attempted ignition for
15 minutes. Check igniter and flame
sensor electrode spacing, gaps, etc.
Check flame sense and igniter wiring.
Check gas valve operation and gas
supply.

6
Induced Draft Motor
Flashes Fault

If heat off: no gas
heating.
If heat on: gas valve
Off and inducer On.

Inducer sense
normal, or heat call
(W) Off.

Inducer sense On when heat call Off, or
inducer sense Off when heat call On.
Check wiring, voltage, and operation of
IGC motor. Check speed sensor wiring to
IGC.

7
Rollout Switch Lockout
Flashes

Gas valve and igniter
Off.
Power reset.
Indoor fan and inducer
On.

Rollout switch has opened. Check gas
valve operation. Check induced-draft
blower wheel is properly secured to motor
shaft.

8
Internal Control Lockout
Flashes

No gas heating.

Power reset.

IGC has sensed internal hardware or
software error. If fault is not cleared by
resetting 24 v power, replace the IGC.
Check gas valve connections to IGC
terminals. BRN lead must be on Pin 11.

9
Temporary Software
Flashes Lockout

No gas heating.

1 hour auto reset, or
power reset.

Electrical interference is disrupting the
IGC software.

LEGEND
IGC --- Integrated Gas Unit Control
LED --- Light--- Emitting Diode
NOTES:
1. There is a 3--- second pause between alarm code displays.
2. If more than one alarm code exists, all applicable alarm codes will be displayed in numerical sequence.
3. Alarm codes on the IGC will be lost if power to the unit is interrupted.

34

Condenser Coil
The condenser coil is new NOVATION Heat Exchanger
Technology. This is an all-- aluminum construction with
louvered fins over single-- depth crosstubes. The crosstubes
have multiple small passages through which the
refrigerant passes from header to header on each end.
Tubes and fins are both aluminum construction.
Connection tube joints are copper. The coil may be
one-- row or two-- row. Two-- row coils are spaced apart to
assist in cleaning.
Repairing NOVATION Condenser Tube Leaks
RCD offers service repair kit Part Number 50TJ660007
for repairing tube leaks in the NOVATION coil crosstubes.
This kit includes approved braze materials (aluminum flux
core braze rods), a heat shield, a stainless steel brush,
replacement fin segments, adhesive for replacing fin
segments, and instructions specific to the NOVATION
aluminum coil. See EPIC for instruction sheet
99TA526379.

The repair procedure requires the use of MAPP gas and
torch (must be supplied by servicer) instead of
conventional oxyacetylene fuel and torch. While the
flame temperature for MAPP is lower than that of
oxyacetylene (and thus provides more flexibility when
working on aluminum), the flame temperature is still
higher than the melting temperature of aluminum, so user
caution is required. Follow instructions carefully. Use the
heat shield.
Replacing NOVATION Condenser Coil
The service replacement coil is preformed and is equipped
with transition joints with copper stub tubes. When
brazing the connection joints to the unit tubing, use a wet
cloth around the aluminum tube at the transition joint.
Avoid applying torch flame directly onto the aluminum
tubing.

Fig. 41 - PremierLinkt Controller

35

C08199

48TC

CONDENSER COIL SERVICE

PREMIERLINKt CONTROL

48TC

The PremierLink controller (see Fig. 41) is compatible
with Carrier Comfort Networkr (CCN) devices. This
control is designed to allow users the access and ability to
change factory-- defined settings, thus expanding the
function of the standard unit control board. CCN service
access tools include System Pilot (TM), Touch Pilot (TM)
and Service Tool. (Standard tier display tools Navigatort
and Scrolling Marquee are not suitable for use with latest
PremierLink controller (Version 2.x).)
The PremierLink control is factory-- mounted in the 48TC
unit’s main control box to the left of the LCTB. Factory
wiring is completed through harnesses connected to the
LCTB thermostat. Field connections are made at a
16-- pole terminal block (TB1) located on the bottom shelf
of the unit control box in front of the PremierLink
controller The factory-- installed PremierLink control
includes the supply-- air temperature (SAT) sensor. The
outdoor air temperature (OAT) sensor is included in the
FIOP/accessory EconoMi$er 2 package.

NOTE: PremierLink controller is shipped in Sensor
mode. To be used with a thermostat, the PremierLink
controller must be configured to Thermostat mode. Refer
to PremierLink Configuration instructions for Operating
Mode.
Supply Air Temperature (SAT) Sensor — On
FIOP-- equipped 48TC unit, the unit is supplied with a
supply-- air temperature (SAT) sensor (33ZCSENSAT).
This sensor is a tubular probe type, approx. 6-- inches (12.7
mm) in length. It is a nominal 10-- k ohm thermistor. See
Table 15 for temperature-- resistance characteristic.
The SAT is factory-- wired. The SAT probe is wire-- tied to
the supply-- air opening (on the horizontal opening end) in
its shipping position. Remove the sensor for installation.
Re-- position the sensor in the flange of the supply-- air
opening or in the supply air duct (as required by local
codes). Drill or punch a 1/2-- in. hole in the flange or duct.
Use two field-- supplied, self-- drilling screws to secure the
sensor probe in a horizontal orientation. (See Fig. 42.)

Refer to Fig. 41 for PremierLink connection locations.
NOTE: Refer to the Rooftop PremierLink Installation,
Start-Up, and Configuration Instructions (Form
33CS-- 58SI) for complete PremierLink configuration,
operating sequences and troubleshooting information.
Have a copy of this manual available at unit start-- up.
The PremierLink controller requires the use of
electronic thermostat or a CCN connection
broadcast to initiate its internal timeclock.
necessary for broadcast of time of day
(occupied/unoccupied).

a Carrier
for time
This is
functions

SUPPLY AIR
TEMPERATURE
SENSOR

ROOF
CURB
SUPPLY AIR

RETURN AIR

C08200

Fig. 42 - Typical Mounting Location for Supply Air
Temperature (SAT) Sensor on Small Rooftop Units

36

37

Fig. 43 - Typical PremierLinkt System Control Wiring Diagram

48TC

C08665

48TC

Table 15 – Thermistor Resistance vs Temperature
Values for Space Temperature Sensor, Supply Air
Temperature Sensor, and Outdoor Air Temperature
Sensor
TEMP
(C)
---40
---35
---30
---25
---20
---15
---10
---5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70

TEMP
(F)
---40
---31
---22
---13
---4
5
14
23
32
41
50
59
68
77
86
95
104
113
122
131
140
149
158

RESISTANCE
(Ohms)
335,651
242,195
176,683
130,243
96,974
72,895
55,298
42,315
32,651
25,395
19,903
15,714
12,494
10,000
8,056
6,530
5,325
4,367
3,601
2,985
2,487
2,082
1,752

Field connections — Field connections for accessory
sensor and input devices are made at the 16-- pole terminal
block (TB1) located on the control box bottom shelf in
front of the PremierLink control. Some input devices also
require a 24-- vac signal source; connect at LCTB terminal
R at “THERMOSTAT” connection strip for this signal
source. See connections figures on following pages for
field connection locations (and for continued connections
at the PremierLink board inputs).
Table 17 provides a summary of field connections for
units equipped with Space Sensor. Table 18 provides a
summary of field connections for units equipped with
Space Thermostat.
Space Sensors — The PremierLink controller is
factory-- shipped configured for Space Sensor Mode. A
Carrier T-- 55 or T-- 56 space sensor must be used. T-- 55
space temperature sensor provides a signal of space
temperature to the PremierLink control T-- 56 provides
same space temperature signal plus it allows for
adjustment of space temperature setpoints from the face of
the sensor by the occupants. See Table 15 for temperature
versus resistance characteristic on the space sensors.
Connect T-- 55 — See Fig. 44 for typical T-- 55 internal
connections. Connect the T-- 55 SEN terminals to TB1
terminals 1 and 3 (see Fig. 45).

NOTE: The sensor must be mounted in the discharge
airstream downstream of the cooling coil and any heating
devices. Be sure the probe tip does not come in contact
with any of the unit’s heater surfaces.

1

2

3

4

5

6
RED(+)
WHT(GND)
BLK(-)

CCN COM

SEN
SW1

Outdoor Air Temperature (OAT) Sensor — The OAT is
factory-- mounted in the EconoMi$er 2 (FIOP or
accessory). It is a nominal 10k ohm thermistor attached to
an eyelet mounting ring. See Table 15 for
temperature-- resistance characteristic.

BRN (GND)
BLU (SPT)

EconoMi$er 2 — The PremierLink control is used with
EconoMi$er 2 (option or accessory) for outdoor air
management. The damper position is controlled directly
by the PremierLink control; EconoMi$er 2 has no internal
logic device.

SENSOR WIRING

C08201

Fig. 44 - T-- 55 Space Temperature Sensor Wiring

Outdoor air management functions can be enhanced with
field-- installation of these accessory control devices:
Enthalpy control (outdoor air or differential sensors)
Space CO2 sensor
Outdoor air CO2 sensor
Refer to Table 16 for accessory part numbers.

TB1

PL

SEN

1

J6-7

SEN

3

J6-6

Fig. 45 - PremierLink T-- 55 Sensor

38

C08212

APPLICATION
Differential Dry Bulb
Temperature with
PremierLink
(PremierLink requires
4---20 mA Actuator)
Single Enthalpy with
PremierLink
(PremierLink requires
4---20mA Actuator)
Differential Enthalpy
with PremierLink
(PremierLink requires
4---20mA Actuator)

OUTDOOR AIR
TEMPERATURE
SENSOR

RETURN AIR
TEMPERATURE
SENSOR

OUTDOOR AIR
ENTHALPY SENSOR

RETURN AIR
ENTHALPY SENSOR

Included --CRTEMPSN001A00

Required --33ZCT55SPT
or equivalent

---

---

Included --Not Used

---

Requires --HH57AC077
or equivalent

---

Included --Not Used

---

Requires --HH57AC077
or equivalent

Requires --HH57AC078
or equivalent

NOTES:
CO2 Sensors (Optional):
33ZCSENCO2 --- Room sensor (adjustable). Aspirator box is required for duct mounting of the sensor.
33ZCASPCO2 --- Aspirator box used for duct--- mounted CO2 room sensor.
33ZCT55CO2 --- Space temperature and CO2 room sensor with override.
33ZCT56CO2 --- Space temperature and CO2 room sensor with override and setpoint.

Table 17 – Space Sensor Mode
TB1 TERMINAL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LEGEND:
T55
T56
CCN
CMPSAFE
FILTER

-----------

FIELD CONNECTION
T55---SEN/T56---SEN
RMTOCC
T55---SEN/T56---SEN
CMPSAFE
T56---SET
FSD
LOOP---PWR
SPS
IAQ ---SEN
FILTER
IAQ ---COM/OAQ ---COM/RH ---COM
CCN + (RED)
OAQ ---SEN/RH ---SEN
CCN Gnd (WHT)
AUX OUT(Power Exhaust)
CCN --- (BLK)

Space Temperature Sensor
Space Temperature Sensor
Carrier Comfort Network (communication bus)
Compressor Safety
Dirty Filter Switch

INPUT SIGNAL
Analog (10k thermistor)
Discrete, 24VAC
Analog (10k thermistor)
Discrete, 24VAC
Analog (10k thermistor)
Discrete, 24VAC
Analog, 24VDC
Discrete, 24VAC
Analog, 4---20mA
Discrete, 24VAC
Analog, 4---20mA
Digital, , 5VDC
Analog, 4---20mA
Digital, 5VDC
(Output)Discrete 24VAC
Digital, 5VDC
FSD
IAQ
OAQ
RH
SFS

39

-----------

Fire Shutdown
Indoor Air Quality (CO2)
Outdoor Air Quality (CO2)
Relative Humidity
Supply Fan Status

48TC

Table 16 – PremierLink Sensor Usage

48TC

Table 18 – Thermostat Mode
TB1 TERMINAL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
LEGEND:
CCN
--G
--IAQ
--OAQ
--RAT
---

FIELD CONNECTION
RAT SEN
G
RAT SEN
Y1

INPUT SIGNAL
Analog (10k thermistor)
Discrete, 24VAC
Analog (10k thermistor)
Discrete, 24VAC

Y2
LOOP---PWR
W1
IAQ ---SEN
W2
IAQ ---COM/OAQ ---COM/RH ---COM
CCN + (RED)
OAQ ---SEN/RH ---SEN
CCN Gnd (WHT)
AUX OUT (Power Exhaust)
CCN --- (BLK)

Discrete, 24VAC
Analog, 24VDC
Discrete, 24VAC
Analog, 4---20mA
Discrete, 24VAC
Analog, 4---20mA
Digital, 5VDC
Analog, 4---20mA
Digital, 5VDC
(Output) Discrete 24VAC
Digital, 5VDC

RH
W1
W2
Y1
Y2

Carrier Comfort Network (communication bus)
Thermostat Fan
Indoor Air Quality (CO2)
Outdoor Air Quality (CO2)
Return Air Temperature

Connect T-- 56 — See Fig. 46 for T-- 56 internal
connections. Install a jumper between SEN and SET
terminals as illustrated. Connect T-- 56 terminals to TB1
terminals 1, 3, and 5 (see Fig. 47).

-----------

Relative Humidity
Thermostat Heat Stage 1
Thermostat Heat Stage 2
Thermostat Cool Stage 1
Thermostat Cool Stage 2

Connect Thermostat — A 7-- wire thermostat connection
requires a 24-- v power source and a common connection.
Use the R and C terminals on the LCTB’s THERMOSTAT
connection strip for these. Connect the thermostat’s Y1,
Y2, W1, W2 and G terminals to PremierLink TB1 as
shown in Fig. 48.
SPACE
THERMOSTAT

1

2

3

4

SEN
SW1

5

6
RED(+)
WHT(GND)
BLK(-)

TB1

SENSOR WIRING

JUMPER
TERMINALS
AS SHOWN

Warm

Fig. 46 - T-- 56 Internal Connections

SEN

SEN

TB1

PL

1

J6-7

TB1
3

PL
J6-6

5

J6-5

C08202

G

2

PL
J4-12

Y1

4

J4-10

Y2

6

J4-8

W1

8

J4-6

W2

10

J4-4

C

C

SET

Fig. 47 - PremierLink T-- 56 Sensor

LCTB
THERMOSTAT

Fig. 48 - Space Thermostat Connections

Jumper

SET

R

R
CCN COM

SET

BLK
(T56)
BRN (GND)
BLU (SPT)

Cool

LCTB
THERMOSTAT

C08213

C08119

If the 48TC unit has an economizer system and
free-- cooling operation is required, a sensor representing
Return Air Temperature must also be connected
(field-- supplied and installed). This sensor may be a T-- 55
Space Sensor (see Fig. 44) installed in the space or in the
return duct, or it may be sensor PNO 33ZCSENSAT,
installed in the return duct. Connect this sensor to TB1-- 1
and TB1-- 3 per Fig. 45. Temperature-- resistance
characteristic is found in Table 15.

40

Return Air Enthalpy Sensor — Mount the return-- air
enthalpy sensor (HH57AC078) in the return-- air duct. The
return air sensor is wired to the enthalpy controller
(HH57AC077). See Fig. 50.
ENTHALPY CONTROLLER

When the PremierLink is configured for Thermostat
Mode, these functions are not available: Fire Shutdown
(FSD), Remote Occupied (RMTOCC), Compressor Safety
(CMPSAFE), Supply Fan Status (SFS), and Filter Pressure
Switch (FILTER).

A

B

TR
C
D SO

TR1

SR

+

2

Economizer controls —

LED

Outdoor Air Enthalpy Control (PNO HH57AC077) The enthalpy control (HH57AC077) is available as a
field-- installed accessory to be used with the EconoMi$er2
damper system. The outdoor air enthalpy sensor is part of
the enthalpy control. (The separate field-- installed
accessory return air enthalpy sensor (HH57AC078) is
required for differential enthalpy control. See Fig. 50.)
Locate the enthalpy control in the economizer hood.
Locate two GRA leads in the factory harness and connect
these leads to enthalpy control sensors 2 and 3. See Fig.
49. Connect the enthalpy control power input terminals to
economizer actuator power leads RED (connect to TR)
and BLK (connect to TR1).

LCTB
ECON

Enthalpy
Switch
2

GRA

6

3

GRA

7

Factory Wiring Harness
C08218

Fig. 49 - Enthalpy Switch (HH57AC077) Connections

The outdoor enthalpy changeover setpoint is set at the
enthalpy controller.
The enthalpy control receives the outdoor air enthalpy
from the outdoor air enthalpy sensor and provides a dry
contact switch input to the PremierLink controller. A
closed contact indicates that outside air is preferred to the
return air. An open contact indicates that the economizer
should remain at minimum position.
Differential Enthalpy Control — Differential enthalpy
control is provided by sensing and comparing the outside
air and return air enthalpy conditions. Install the outdoor
air enthalpy control as described above. Add and install a
return air enthalpy sensor.

+

RED
BRN

BLK
RED

S (RETURN AIR
+ ENTHALPY
SENSOR)

3
1

S (OUTDOOR
AIR
+ ENTHALPY
SENSOR)

GRAY/ORN
GRAY/RED

WIRE HARNESS
IN UNIT

NOTES:
1. Remove factory-installed jumper across SR and + before connecting
wires from return air sensor.
2. Switches shown in high outdoor air enthalpy state. Terminals 2 and 3
close on low outdoor air enthalpy relative to indoor air enthalpy.
3. Remove sensor mounted on back of control and locate in outside airstream.
C06019

Fig. 50 - Outside and Return Air Enthalpy Sensor
Wiring

To wire the return air enthalpy sensor, perform the
following:
1. Use a 2-- conductor, 18 or 20 AWG, twisted pair cable
to connect the return air enthalpy sensor to the
enthalpy controller.
2. At the enthalpy control remove the factory-- installed
resistor from the (SR) and (+) terminals.
3. Connect the field-- supplied RED wire to (+) spade
connector on the return air enthalpy sensor and the
(SR+) terminal on the enthalpy controller. Connect
the BLK wire to (S) spade connector on the return air
enthalpy sensor and the (SR) terminal on the enthalpy
controller.
NOTE: The enthalpy control must be set to the “D”
setting for differential enthalpy control to work properly.
The enthalpy control receives the indoor and return
enthalpy from the outdoor and return air enthalpy sensors
and provides a dry contact switch input to the
PremierLink controller. A closed contact indicates that
outside air is preferred to the return air. An open contact
indicates that the economizer should remain at minimum
position.
Indoor Air Quality (CO2 sensor) — The indoor air quality
sensor accessory monitors space carbon dioxide (CO2)
levels. This information is used to monitor IAQ levels.
Several types of sensors are available, for wall mounting
in the space or in return duct, with and without LCD
display, and in combination with space temperature
sensors. Sensors use infrared technology to measure the
levels of CO2 present in the space air.

41

48TC

Configure the unit for Thermostat Mode — Connect to the
CCN bus using a CCN service tool and navigate to
PremierLink Configuration screen for Operating Mode.
Default setting is Sensor Mode (value 1). Change the
value to 0 to reconfigure the controller for Thermostat
Mode.

The CO2 sensors are all factory set for a range of 0 to
2000 ppm and a linear mA output of 4 to 20. Refer to the
instructions supplied with the CO2 sensor for electrical
requirements and terminal locations. See Fig. 51 for
typical CO2 sensor wiring schematic.
Fig. 52 - Indoor CO2 Sensor (33ZCSENCO2)
Connections

C09155

Refer to the Rooftop PremierLink Installation, Start-Up,
and Configuration Instructions (Form 33CS-- 58SI),
PremierLink Installation, Start-- up, and Configuration
Instructions, for detailed configuration information

48TC

Outdoor Air Quality Sensor (PNO 33ZCSENCO2 plus
weatherproof enclosure) — The outdoor air CO2 sensor is
designed to monitor carbon dioxide (CO2) levels in the
outside ventilation air and interface with the ventilation
damper in an HVAC system. The OAQ sensor is packaged
with an outdoor cover. See Fig. 53. The outdoor air CO2
sensor must be located in the economizer outside air hood.

C07134

Fig. 51 - Indoor/Outdoor Air Quality (CO2) Sensor
(33ZCSENCO2) - Typical Wiring Diagram

To accurately monitor the quality of the air in the
conditioned air space, locate the sensor near a return-- air
grille (if present) so it senses the concentration of CO2
leaving the space. The sensor should be mounted in a
location to avoid direct breath contact.
Do not mount the IAQ sensor in drafty areas such as near
supply ducts, open windows, fans, or over heat sources.
Allow at least 3 ft (0.9 m) between the sensor and any
corner. Avoid mounting the sensor where it is influenced
by the supply air; the sensor gives inaccurate readings if
the supply air is blown directly onto the sensor or if the
supply air does not have a chance to mix with the room air
before it is drawn into the return airstream.
Wiring the Indoor Air Quality Sensor —
For each sensor, use two 2-- conductor 18 AWG (American
Wire Gage) twisted-- pair cables (unshielded) to connect
the separate isolated 24 vac power source to the sensor
and to connect the sensor to the control board terminals.
To connect the sensor to the control, identify the positive
(4 to 20 mA) and ground (SIG COM) terminals on the
sensor. See Fig. 51. Connect the 4-- 20 mA terminal to
terminal TB1-- 9 and connect the SIG COM terminal to
terminal TB1-- 11. See Fig. 52.

COVER REMOVED

SIDE VIEW

Fig. 53 - Outdoor Air Quality Sensor Cover

C07135

Wiring the Outdoor Air CO2 Sensor — A dedicated power
supply is required for this sensor. A two-- wire cable is
required to wire the dedicated power supply for the sensor.
The two wires should be connected to the power supply
and terminals 1 and 2.
To connect the sensor to the control, identify the positive
(4 to 20 mA) and ground (SIG COM) terminals on the
OAQ sensor. See Fig. 51. Connect the 4 to 20 mA
terminal to 48TC’s terminal TB1-- 13. Connect the SIG
COM terminal to 48TC’s terminal TB1-- 11. See Fig. 54.
OAQ Sensor/RH Sensor
SEN

TB1
13

PL
J5-2

COM

TB1
11

J5-3

24 VAC

Fig. 54 - Outdoor CO2 Sensor Connections

42

C08275

Smoke Detector/Fire Shutdown (FSD) — This function is
available only when PremierLink is configured for
(Space) Sensor Mode. The unit is factory-- wired for
PremierLink FSD operation when PremierLink is
factory-- installed.
On 48TC units equipped with factory-- installed Smoke
Detector(s), the smoke detector controller implements the
unit shutdown through its NC contact set connected to the
unit’s LCTB input. The FSD function is initiated via the
smoke detector’s Alarm NO contact set. The PremierLink
communicates the smoke detector’s tripped status to the
CCN building control. See Fig. 25 for unit smoke detector
wiring.
Alarm state is reset when the smoke detector alarm
condition is cleared and reset at the smoke detector in the
unit.

Supply Fan Status Switch — The PremierLink control can
monitor
supply
fan
operation
through
a
field-- supplied/installed differential pressure switch. This
sequence will prevent (or interrupt) operation of unit
cooling, heating and economizer functions until the
pressure switch contacts are closed indicating proper
supply fan operation.
Install the differential pressure switch in the supply fan
section according to switch manufacturer’s instructions.
Arrange the switch contact to be open on no flow and to
close as pressure rises indicating fan operation.
Connect one side of the switch’s NO contact set to
LCTB’s THERMOSTAT-- R terminal. Connect the other
side of the NO contact set to TB1-- 8. Setpoint for Supply
Fan Status is set at the switch. See Fig. 56.
Fan (Pressure) Switch (NO, close on rise in pressure)
LCTB
Thermostat
R
TB1

Using switch input: Install the dirty filter pressure switch
according to switch manufacturer’s instructions, to
measure pressure drop across the unit’s return filters.
Connect one side of the switch’s NO contact set to
LCTB’s THERMOSTAT-- R terminal. Connect the other
side of the NO contact set to TB1-- 10. Setpoint for Dirty
Filter is set at the switch. See Fig. 55.
Filter Switch (NO, close on rising pressure (high drop))
LCTB
Thermostat
R
TB1
10

PL
J4-6

8

Filter Status Switch — This function is available only
when PremierLink is configured for (Space) Sensor Mode.
PremierLink control can monitor return filter status in two
ways: By monitoring a field-- supplied/installed filter
pressure switch or via supply fan runtime hours.

C08118

Fig. 56 - PremierLink Wiring Fan Pressure Switch
Connection

Remote Occupied Switch — The PremierLink control
permits a remote timeclock to override the control’s
on-- board occupancy schedule and place the unit into
Occupied mode. This function may also provide a “Door
Switch” time delay function that will terminate cooling
and heating functions after a 2-- 20 minute delay.
Connect one side of the NO contact set on the timeclock
to LCTB’s THERMOSTAT-- R terminal. Connect the other
side of the timeclock contact to the unit’s TB1-- 2 terminal.
See Fig. 57.
Remote Occupied

LCTB
Thermostat

Time Clock

TB1

PL
J4-4

R

2
C08216

Using Filter Timer Hours: Refer to the Rooftop
PremierLink Installation, Start-Up, and Configuration
Instructions (Form 33CS-- 58SI) for instructions on using
the PremierLink Configuration screens and on unit alarm
sequence.

PL
J4-12
C08214

Fig. 55 - PremierLink Filter Switch Connection

When the filter switch’s NO contact set closes as filter
pressure drop increases (indicating dirt-- laden filters), the
input signal to PremierLink causes the filter status point to
read “DIRTY”.

48TC

Refer to the Rooftop PremierLink Installation, Start-Up,
and Configuration Instructions (Form 33CS-- 58SI),
PremierLink Installation, Start-- up, and Configuration
Instructions, for detailed configuration information.

Fig. 57 - PremierLink Wiring Remote Occupied

Refer to the Rooftop PremierLink Installation, Start-Up,
and Configuration Instructions (Form 33CS-- 58SI) for
additional information on configuring the PremierLink
control for Door Switch timer function.
Power Exhaust (output) - Connect the accessory Power
Exhaust contactor coils(s) per Fig. 58.

43

Power Exhaust
PEC

TB1
TAN

GRA

15
LCTB
THERMOSTAT
C

Connecting CCN bus:
PL
J8-3

NOTE: When connecting the communication bus cable,
a color code system for the entire network is
recommended to simplify installation and checkout. See
Table 20 for the recommended color code.
Table 20 – Color Code Recommendations

48TC

C08120

Fig. 58 - PremierLinkt Power Exhaust Output
Connection

SIGNAL TYPE

Space Relative Humidity Sensor — The RH sensor is not
used with 48TC models at this time.

+
Ground
---

CCN Communication Bus — The PremierLink controller
connects to the bus in a daisy chain arrangement.
Negative pins on each component must be connected to
respective negative pins, and likewise, positive pins on
each component must be connected to respective positive
pins. The controller signal pins must be wired to the signal
ground pins. Wiring connections for CCN must be made
at the 3-- pin plug.
At any baud (9600, 19200, 38400 baud), the number of
controllers is limited to 239 devices maximum. Bus length
may not exceed 4000 ft (1219m), with no more than 60
total devices on any 1000-- ft (305m) section. Optically
isolated RS-- 485 repeaters are required every 1000 ft
(305m).

See Table 19 for recommended cable.
Table 19 – Recommended Cables
MANUFACTURER
Alpha
American
Belden
Columbia

CABLE PART NO.
2413 or 5463
A22503
8772
02525

NOTE: Conductors and drain wire must be at least 20
AWG, stranded, and tinned copper. Individual conductors
must be insulated with PVC, PVC/nylon, vinyl, Teflon, or
polyethylene. An aluminum/polyester 100% foil shield
and an outer jacket of PVC, PVC/nylon, chrome vinyl, or
Teflon with a minimum operating temperature range of
- 20 C to 60 C is required. Do not run communication wire
in the same conduit as or next to any AC voltage wiring.
The communication bus shields must be tied together at
each system element. If the communication bus is entirely
within one building, the resulting continuous shield must
be connected to ground at only one single point. If the
communication bus cable exits from one building and
enters another building, the shields must be connected to
the grounds at a lightning suppressor in each building (one
point only).

CCN PLUG PIN
NUMBER
1
2
3

Connect the CCN (+) lead (typically RED) to the unit’s
TB1-- 12 terminal. Connect the CCN (ground) lead
(typically WHT) to the unit’s TB1-- 14 terminal. Connect
the CCN (-- ) lead (typically BLK) to the unit’s TB1-- 16
terminal. See Fig. 59.
CCN Bus
+ (RED)

TB1
12

PL
J2-1

GND (WHT)

TB1
14

J2-2

– (BLK)

TB1
16

J2-3

NOTE: Carrier device default is 9600 baud.
COMMUNICATION BUS WIRE SPECIFICATIONS —
The CCN Communication Bus wiring is field-- supplied
and field-- installed. It consists of shielded 3-- conductor
cable with drain (ground) wire. The cable selected must
be identical to the CCN Communication Bus wire used for
the entire network.

CCN BUS WIRE
COLOR
Red
White
Black

Fig. 59 - PremierLink CCN Bus Connections

C08276

RTU--MP CONTROL SYSTEM
The RTU-- MP controller, see Fig. 60, provides expanded
stand-- alone operation of the HVAC system plus
connection and control through communication with
several Building Automation Systems (BAS) through
popular third-- party network systems. The available
network systems are BACnet MP/TP, Modbus and
Johnson J2. Communication with LonWorks is also
possible by adding an accessory interface card to the
RTU-- MP. Selection of the communication protocol and
baud rate are made at on-- board DIP switches.
Carrier’s diagnostic display tools BACviewer6 Handheld
and Virtual BACview (loaded on a portable PC) must be
used with the RTU-- MP controller. Connection to the
RTU-- MP board is at the J12 access port, see Fig. 60.
The RTU-- MP control is factory-- mounted in the 48TC
unit’s main control box, to the left of the LCTB. See Fig.
61. Factory wiring is completed through harnesses
connected to the LCTB. Field connections for RTU-- MP
sensors will be made at the Phoenix connectors on the
RTU-- MP board. The factory-- installed RTU-- MP control
includes the supply-- air temperature (SAT) sensor. The
outdoor air temperature (OAT) sensor is included in the
FIOP/accessory EconoMi$er 2 package.
Refer to Table 21, RTU-- MP Controller Inputs and
Outputs, for locations of all connections to the RTU-- MP
board.

44

48TC
Fig. 60 - RTU-- MP Multi-- Protocol Control Board

45

C07129

46

Fig. 61 - Typical RTU-- MP System Control Wiring Diagram

48TC

C09163

Table 21 – RTU-- MP Controller Inputs and Outputs

Space Temperature Sensor
Supply Air Temperature
Local Outside Air Temperature Sensor
Space Temperature Offset Pot
Indoor Air Quality
Outdoor Air Quality
Safety Chain Feedback
Compressor Safety
Fire Shutdown
Enthalpy Switch
Humidistat Input Status
Space Relative Humidity
Outside Air Relative Humidity
Supply Fan Status
Filter Status
Remote Occupancy Input
Economizer Commanded Position
Supply Fan Relay State
Compressor 1 Relay State
Compressor 2 Relay State
Heat Stage 1 Relay State
Heat Stage 2 Relay State
Power Exhaust Relay State
Dehumidification Relay State

BACnet OBJECT
TYPE OF I/O
NAME
INPUTS
sptsens
AI (10K Thermistor)
sat
AI (10K Thermistor)
oatsens
AI (10K Thermistor)
sptopot
AI (100K Potentiometer)
iaq
AI (4---20 ma)
oaq
AI (4---20 ma)
safety
DI (24 VAC)
compstat
DI (24 VAC)
firedown
DI (24 VAC)
enthalpy
DI (24 VAC)
humstat
DI (24 VAC)
CONFIGURABLE INPUTS*
sprh
AI (4---20 ma)
oarh
AI (4---20 ma)
fanstat
DI (24 VAC)
filtstat
DI (24 VAC)
remocc
DI (24 VAC)
OUTPUTS
econocmd
4---20ma
sf
DO Relay (24VAC , 1A)
comp_1
DO Relay (24VAC , 1A)
comp_2
DO Relay (24VAC , 1A)
heat_1
DO Relay (24VAC , 1A)
heat_2
DO Relay (24VAC , 1A)
aux_2
DO Relay (24VAC , 1A)
humizer
DO Relay (24VAC, 1A)

CONNECTION PIN
NUMBERS
J20---1, 2
J2---1, 2
J2---3, 4
J20---3
J4---2, 3
J4---5, 6
J1---9
J1---2
J1---10
J2---6, 7
J5---7, 8
J4---2,3 or J4---5,6
J5---1,2 or J5---3,4 or
J5 5,6 or J5---7,8
J2---5
J1---4
J1---8
J1---7
J1---6
J1---5
J11---3
J11---7, 8

LEGEND
AI --- Analog Input
AO --- Analog Output
DI --- Discrete Input
DO --- Discrete Output
* These inputs (if installed) take the place of the default input on the specific channel according to schematic.
Parallel pins J5--- 1 = J2--- 6, J5--- 3 = J1--- 10, J5--- 5 = J1--- 2 are used for field --- installation.
Refer to the input configuration and accessory sections for more detail.

NOTE: Refer to RTU-- MP Controls, Start-Up, Operation,
and Troubleshooting Instructions (Form 48-- 50H-- T-- 2T)
for complete configuration of RTU-- MP, operating
sequences and troubleshooting information. Refer to
RTU-- MP 3rd Party Integration Guide for details on
configuration and troubleshooting of connected networks.
Have a copy of these manuals available at unit start-- up.
The RTU-- MP controller requires the use of a Carrier
space sensor. A standard thermostat cannot be used with
the RTU-- MP system.
Supply Air Temperature (SAT) Sensor — On
FIOP-- equipped 48TC unit, the unit is supplied with a
supply-- air temperature (SAT) sensor (33ZCSENSAT).
This sensor is a tubular probe type, approx 6-- inches (12.7
mm) in length. It is a nominal 10-- k ohm thermistor. See
Table 15 for temperature-- resistance characteristic.

The SAT is factory-- wired. The SAT probe is wire-- tied to
the supply-- air opening (on the horizontal opening end) in
its shipping position. Remove the sensor for installation.
Re-- position the sensor in the flange of the supply-- air
opening or in the supply air duct (as required by local
codes). Drill or punch a 1/2-- in. hole in the flange or duct.
Use two field-- supplied, self-- drilling screws to secure the
sensor probe in a horizontal orientation. See Fig. 42.
Outdoor Air Temperature (OAT) Sensor — The OAT is
factory-- mounted in the EconoMi$er 2 (FIOP or
accessory). It is a nominal 10k ohm thermistor attached to
an eyelet mounting ring. See Table 15 for
temperature-- resistance characteristic.
EconoMi$er 2 — The RTU-- MP control is used with
EconoMi$er2 (option or accessory) for outdoor air
management. The damper position is controlled directly
by the RTU-- MP control; EconoMi$er 2 has no internal
logic device.

47

48TC

POINT NAME

Outdoor air management functions can be enhanced with
field-- installation of these accessory control devices:

48TC

Enthalpy control (outdoor air or differential sensors)
Space CO2 sensor
Outdoor air CO2 sensor
Field Connections - Field connections for accessory
sensors and input devices are made the RTU-- MP, at plugs
J1, J2, J4, J5, J11 and J20. All field control wiring that
connects to the RTU-- MP must be routed through the
raceway built into the corner post as shown in Fig. 36.
The raceway provides the UL required clearance between
high-- and low-- voltage wiring. Pass the control wires
through the hole provided in the corner post, then feed the
wires thorough the raceway to the RTU-- MP. Connect to
the wires to the removable Phoenix connectors and then
reconnect the connectors to the board.

Space Temperature (SPT) Sensors

SEN

J20-1

SEN

J20-2
Jumper

SET
SET

J20-3

Fig. 63 - RTU-- MP T-- 56 Sensor Connections

Connect T-- 59 — The T-- 59 space sensor requires a
separate, isolated power supply of 24 VAC. See Fig. 64
for internal connections at the T-- 59. Connect the SEN
terminal (BLU) to RTU-- MP J20-- 1. Connect the COM
terminal (BRN) to J20-- 2. Connect the SET terminal (STO
or BLK) to J20-- 3.

A field-- supplied Carrier space temperature sensor is
required with the RTU-- MP to monitor space temperature.
There are 3 sensors available for this application:

BRN (COM)
BLK (STO)

S 33ZCT55SPT, space temperature sensor with override
button
S 33ZCT56SPT, space temperature sensor with override
button and setpoint adjustment
S 33ZCT59SPT, space temperature sensor with LCD
(liquid crystal display) screen, override button, and
setpoint adjustment

BLU (SPT)

OR

Use 20 gauge wire to connect the sensor to the controller.
The wire is suitable for distances of up to 500 ft. Use a
three-- conductor shielded cable for the sensor and setpoint
adjustment connections. If the setpoint adjustment
(slidebar) is not required, then an unshielded, 18 or 20
gauge, two-- conductor, twisted pair cable may be used.

J20-1

SEN

J20-2

SET

SEN

OPB

COM- PWR+

24 VAC

SENSOR
WIRING

POWER
WIRING

NOTE: Must use a separate isolated transformer.

Connect T-- 55 — See Fig. 44 for typical T-- 55 internal
connections. Connect the T-- 55 SEN terminals to
RTU-- MP J20-- 1 and J20-- 2. (See Fig. 62.)
SEN

C08461

C07132

Fig. 64 - Space Temperature Sensor Typical Wiring
(33ZCT59SPT)
Economizer controls —

Fig. 62 - RTU-- MP T-- 55 Sensor Connections

Outdoor Air Enthalpy Control (PNO HH57AC077) C08460

Connect T-- 56 — See Fig. 46 for T-- 56 internal
connections. Install a jumper between SEN and SET
terminals as illustrated. Connect T-- 56 terminals to
RTU-- MP J20-- 1, J20-- 2 and J20-- 3 per Fig. 63.

The enthalpy control (HH57AC077) is available as a
field-- installed accessory to be used with the EconoMi$er2
damper system. The outdoor air enthalpy sensor is part of
the enthalpy control. (The separate field-- installed
accessory return air enthalpy sensor (HH57AC078) is
required for differential enthalpy control. See below.)

48

The outdoor enthalpy changeover setpoint is set at the
enthalpy controller.
The enthalpy control receives the outdoor air enthalpy
from the outdoor air enthalpy sensor and provides a dry
contact switch input to the RTU-- MP controller. A closed
contact indicates that outside air is preferred to the return
air. An open contact indicates that the economizer should
remain at minimum position.
Differential Enthalpy Control — Differential enthalpy
control is provided by sensing and comparing the outside
air and return air enthalpy conditions. Install the outdoor
air enthalpy control as described above. Add and install a
return air enthalpy sensor.

The CO2 sensors are all factory set for a range of 0 to
2000 ppm and a linear mA output of 4 to 20. Refer to the
instructions supplied with the CO2 sensor for electrical
requirements and terminal locations. See Fig. 51 for
typical CO2 sensor wiring schematic.
To accurately monitor the quality of the air in the
conditioned air space, locate the sensor near a return-- air
grille (if present) so it senses the concentration of CO2
leaving the space. The sensor should be mounted in a
location to avoid direct breath contact.
Do not mount the IAQ sensor in drafty areas such as near
supply ducts, open windows, fans, or over heat sources.
Allow at least 3 ft (0.9 m) between the sensor and any
corner. Avoid mounting the sensor where it is influenced
by the supply air; the sensor gives inaccurate readings if
the supply air is blown directly onto the sensor or if the
supply air does not have a chance to mix with the room air
before it is drawn into the return airstream.
Wiring the Indoor Air Quality Sensor —

Return Air Enthalpy Sensor — Mount the return-- air
enthalpy sensor (HH57AC078) in the return-- air duct. The
return air sensor is wired to the enthalpy controller
(HH57AC077). (See Fig. 50.)

For each sensor, use two 2-- conductor 18 AWG (American
Wire Gage) twisted-- pair cables (unshielded) to connect
the separate isolated 24 vac power source to the sensor
and to connect the sensor to the control board terminals.

To wire the return air enthalpy sensor, perform the
following:

To connect the sensor to the control, identify the positive
(4 to 20 mA) and ground (SIG COM) terminals on the
sensor. See Fig. 51. Connect the 4-- 20 mA terminal to
RTU-- MP J4-- 2 and connect the SIG COM terminal to
RTU-- MP J4-- 3. See Fig. 65.

1. Use a 2-- conductor, 18 or 20 AWG, twisted pair cable
to connect the return air enthalpy sensor to the
enthalpy controller.
2. At the enthalpy control remove the factory-- installed
resistor from the (SR) and (+) terminals.
3. Connect the field-- supplied RED wire to (+) spade
connector on the return air enthalpy sensor and the
(SR+) terminal on the enthalpy controller. Connect
the BLK wire to (S) spade connector on the return air
enthalpy sensor and the (SR) terminal on the enthalpy
controller.
NOTE: The enthalpy control must be set to the “D”
setting for differential enthalpy control to work properly.
The enthalpy control receives the indoor and return
enthalpy from the outdoor and return air enthalpy sensors
and provides a dry contact switch input to the RTU-- MP
controller. A closed contact indicates that outside air is
preferred to the return air. An open contact indicates that
the economizer should remain at minimum position.
Indoor Air Quality (CO2 sensor) — The indoor air quality
sensor accessory monitors space carbon dioxide (CO2)
levels. This information is used to monitor IAQ levels.
Several types of sensors are available, for wall mounting
in the space or in return duct, with and without LCD
display, and in combination with space temperature
sensors. Sensors use infrared technology to measure the
levels of CO2 present in the space air.

IAQ Sensor
SEN

J4-2

COM

J4-3

24 VAC

Fig. 65 - RTU-- MP / Indoor CO2 Sensor
(33ZCSENCO2) Connections

C08462

Outdoor Air Quality Sensor (PNO 33ZCSENCO2 plus
weatherproof enclosure) — The outdoor air CO2 sensor is
designed to monitor carbon dioxide (CO2) levels in the
outside ventilation air and interface with the ventilation
damper in an HVAC system. The OAQ sensor is packaged
with an outdoor cover. (See Fig. 53.) The outdoor air CO2
sensor must be located in the economizer outside air hood.
Wiring the Outdoor Air CO2 Sensor — A dedicated power
supply is required for this sensor. A two-- wire cable is
required to wire the dedicated power supply for the sensor.
The two wires should be connected to the power supply
and terminals 1 and 2.

49

48TC

Locate the enthalpy control in the economizer hood.
Locate two GRA leads in the factory harness and connect
these leads to enthalpy control sensors 2 and 3. (See Fig.
49.) Connect the enthalpy control power input terminals to
economizer actuator power leads RED (connect to TR)
and BLK (connect to TR1).

To connect the sensor to the control, identify the positive
(4 to 20 mA) and ground (SIG COM) terminals on the
OAQ sensor. See Fig. 51. Connect the 4 to 20 mA
terminal to RTU-- MP J4-- 5. Connect the SIG COM
terminal to RTU-- MP J4-- 6. (See Fig. 66.)
OAQ Sensor/RH Sensor
SEN

J4-5

COM

J4-6

48TC

24 VAC

Fig. 66 - RTU-- MP / Outdoor CO2 Sensor
(33ZCSENCO2) Connections

C08463

Remote Occupancy
The remote occupancy accessory is a field-- installed
accessory. This accessory overrides the unoccupied mode
and puts the unit in occupied mode. When installing this
accessory, the unit must be configured for remote
occupancy by setting MENU→Config→Inputs→input 3,
5, 8, or 9 to Remote Occupancy and normally open (N/O)
or normally closed (N/C).
Also set MENU→Schedules→occupancy source to DI
on/off. Input 8 or 9 is recommended for easy of
installation. Refer to Fig. 60 and Table 21 for wire
terminations at J5.

Power Exhaust (output)
Connect the accessory Power Exhaust contactor coil(s) per
Fig. 67.

Power Exhaust

On 48TC units equipped with factory-- installed Smoke
Detector(s), the smoke detector controller implements the
unit shutdown through its NC contact set connected to the
unit’s LCTB input. The FSD function is initiated via the
smoke detector’s Alarm NO contact set. The RTU-- MP
controler communicates the smoke detector’s tripped
status to the BAS building control. See Fig. 25 for unit
smoke detector wiring.
The
Fire
Shutdown
Switch
configuration,
identifies the
MENU→Config→Inputs→input 5,
normally open status of this input when there is no fire
alarm.
Alarm state is reset when the smoke detector alarm
condition is cleared and reset at the smoke detector in the
unit.

Connecting Discrete Inputs
Filter Status
The filter status accessory is a field-- installed accessory.
This accessory detects plugged filters. When installing
this accessory, the unit must be configured for filter status
by setting MENU→Config→Inputs→input 3, 5, 8, or 9
to Filter Status and normally open (N/O) or normally
closed (N/C). Input 8 or 9 is recommended for easy of
installation. Refer to Fig. 60 and 61 for wire terminations
at J5.
Fan Status
The fan status accessory is a field-- installed accessory.
This accessory detects when the indoor fan is blowing air.
When installing this accessory, the unit must be
configured
for
fan
status
by
setting
MENU→Config→Inputs→input 3, 5, 8, or 9 to Fan
Status and normally open (N/O) or normally closed (N/C).
Input 8 or 9 is recommended for easy of installation. Refer
to Fig. 60 and 61 for wire terminations at J5.

PEC

J11-3

TAN

GRA

LCTB
THERMOSTAT
C
C08464

Fig. 67 - RTU-- MP Power Exhaust Connections

Space Relative Humidity Sensor - The RH sensor is not
used with 48TC models at this time.

Communication Wiring -- Protocols
General
Protocols are the communication languages spoken by
control devices. The main purpose of a protocol is to
communicate information in the most efficient method
possible. Different protocols exist to provide different
kinds of information for different applications. In the BAS
application, many different protocols are used, depending
on manufacturer. Protocols do not change the function of
a controller; just make the front end user different.
The RTU-- MP can be set to communicate on four different
protocols: BACnet, Modbus, N2, and LonWorks. Switch 3
(SW3) on the board is used to set protocol and baud rate.
Switches 1 and 2 (SW1 and SW2) are used to set the
board’s network address. See Fig 68 for the switch setting
per protocol. The 3rd party connection to the RTU-- MP is
through plug J19. Refer to the RTU-- MP 3rd Party
Integration Guide for more detailed information on
protocols, 3rd party wiring, and networking.
NOTE: Power must be cycled after changing the SW1-- 3
switch settings.

50

SW3 Protocol Selection
PROTOCOL
BACnet MS/TP
(Master)
Modbus
(Slave)
N2
(Slave)
LonWorks

DS8

DS7

DS6

DS5

DS4

DS3

DS2

DS1

Unused

OFF

OFF

OFF

ON

OFF

Select Baud

Select Baud

Unused

OFF

OFF

ON

ON

OFF

Select Baud

Select Baud

Unused

OFF

OFF

OFF

ON

ON

OFF

OFF

Unused

ON

ON

OFF

ON

OFF

OFF

OFF

NOTE:
DS = Dip Switch
BACnet MS/TP SW3 example shown

DS2
OFF
ON
OFF
ON

DS1
OFF
OFF
ON
ON

Fig. 68 - RTU-- MP SW3 Dip Switch Settings
BACnet MS/TP
BACnet Master Slave/Token Passing (MS/TP) is used for
communicating BACnet over a sub-- network of
BACnet-- only controllers. This is the default Carrier
communications protocol. Each RTU-- MP module acts as
an MS/TP Master. The speed of an MS/TP network can
range from 9600 to 76.8K baud. Physical Addresses can
be set from 01 to 99.
Modbus
The RTU-- MP module can speak the Modicon Modbus
RTU Protocol as described in the Modicon Modbus
Protocol Reference Guide, PI-- MBUS-- 300 Rev. J. The
speed of a Modbus network can range from 9600 to 76.8K
baud. Physical Addresses can be set from 01 to 99.
Johnson N2
N2 is not a standard protocol, but one that was created by
Johnson Controls, Inc. that has been made open and
available to the public. The speed of N2 network is
limited to only 9600 baud. Physical Addresses can be set
from 01 to 99.
LonWorks
LonWorks is an open protocol that requires the use of
Echelon’s Neuron microprocessor to encode and decode
the LonWorks packets. In order to reduce the cost of
adding that hardware on every module, a separate
LonWorks Option Card (LON-- OC) was designed to
connect to the RTU-- MP.
This accessory card is needed for LonWorks and has to be
ordered and connected using the ribbon cable to plug J15.
The RTU-- MP’s baud rate must be set to 38.4k to
communicate with the LON-- OC. The address switches
(SW1 & SW2) are not used with LonWorks.

C07166

Local Access
BACview6 Handheld

The BACview6 is a keypad/display interface used to
connect to the RTU-- MP to access the control information,
read sensor values, and test the RTU, see Fig. 69. This is
an accessory interface that does not come with the MP
controller and can only be used at the unit. Connect the
BACview6 to the RTU-- MP’s J12 local access port. There
are 2 password protected levels in the display (User and
Admin). The user password defaults to 0000 but can be
changed. The Admin password is 1111 and cannot be
changed. There is a 10 minute auto logout if a screen is
left idle. See RTU-- MP Controls, Start-- Up, Operation, and
Troubleshooting Instructions (Form 48-- 50H-- T-- 2T),
Appendix A for navigation and screen content.
Virtual BACview

Virtual BACview is a freeware computer program that
functions as the BACview6 Handheld. The USB Link
interface (USB-- L) is required to connect a computer to
the RTU-- MP board. The link cable connects a USB port
to the J12 local access port. This program functions and
operates identical to the handheld.

RTU--MP Troubleshooting
Communication LEDs
The LEDs indicate if the controller is speaking to the
devices on the network. The LEDs should reflect
communication traffic based on the baud rate set. The
higher the baud rate the more solid the LEDs will appear.

51

48TC

Baud Rate Selections
BAUD RATE
9600
19,200
38,400
76,800

48TC

Fig. 69 - BACview6 Handheld Connections

C07170

Table 22 – LEDs
The LEDs on the RTU-- MP show the status of certain functions
Status is...
The RTU MP has power
The RTU MP is receiving data from the network segment
The RTU MP is transmitting data over the network segment
The digital output is active

If this LED is on...
Power
Rx
Tx
DO#

The Run and Error LEDs indicate control module and network status
If Run LED shows...
2 flashes per second
2 flashes per second
2 flashes per second
2 flashes per second

And Error LED shows...
Off
2 flashes,
alternating with Run LED
3 flashes,
then off
4 flashes,
then pause

2 flashes per second

On

5 flashes per second

On

5 flashes per second

Off

7 flashes per second
14 flashes per second

On

7 flashes per second, alternating with
Run LED
14 flashes per second,
alternating with Run LED
On

52

Status is...
Normal
Five minute auto---restart delay after
system error
Control module has just been
formatted
Two or more devices on this network
have the same ARC156 network address
Exec halted after frequent system errors
or control programs halted
Exec start---up aborted, Boot is running
Firmware transfer in progress, Boot is
running
Ten second recovery period after
brownout
Brownout
Failure. Try the following solutions:
S
Turn the RTU ---MP off, then on.
S
Format the RTU ---MP.
S
Download memory to the RTU ---MP.
S
Replace the RTU ---MP.

Table 23 – Troubleshooting Alarms

Safety Chain Alarm

safety_chain

Fire Shutdown Alarm

fire_alarm

Space Temp Sensor
Failure

spt_alarm

SAT Sensor Alarm

sat_alarm

High Space Temp Alarm

spt_hi

Alarm Generated

Automatic

Low Space Temp Alarm

spt_lo

Alarm Generated

Automatic

High Supply Air Temp

sat_hi

Alarm Generated

Automatic

Low Supply Air Temp

sat_lo

Alarm Generated

Automatic

Supply Fan Failed to
Start

sf_fail

Supply Fan in Hand

sf_hand

Compressor Safety
Alarm

dx_compstat

Setpoint Slider Alarm

slide_alarm

Dirty Filter Alarm

filter

ACTION TAKEN BY
CONTROL
Alarm Generated
Immediate
Shutdown
Alarm Generated
Immediate
Shutdown
Alarm Generated
Immediate
Shutdown
Alarm Generated
Immediate
Shutdown

Alarm Generated
Immediately
disable Operation
Alarm Generated
Ramp down
Operations

RESET
METHOD
Automatic

Over load Indoor Fan or Electric Heater overheat.

Automatic

Smoke detected by smoke detector or
configuration incorrect

Automatic

Faulty, shorted, or open thermistor caused by
wiring error or loose connection.

Automatic

Faulty, shorted, or open thermistor caused by
wiring error or loose connection.

Automatic

The space temperature has risen above the cool
setpoint by more than the desired amount.
The space temperature has dropped below the
heat setpoint by more than the desired amount.
SAT is greater then 160 degrees for more than 5
minutes.
The supply air temperature is below 35_F for
more than 5 minutes.
Tripped Circuit Breaker, Broken belt, Bad indoor
fan motor, Configuration incorrect, Bad fan status
switch.

Automatic

Bad Fan Status Switch, Configuration incorrect.

Alarm Generated

Automatic

Compressor would not start.

Alarm Generated
Offset set to zero

Automatic

STO sensor is open or shorted for more then 5
seconds.

Alarm Generated

Alarm Generated
Disable
misconfigured switch
functions
Alarm Generated
Disable 4 selectable
analog inputs
Alarm Generated
Economizer and Low
ambient DX cooling
lockout disabled.
Alarm Generated
Dehumidification
disabled

Automatic/re
set timer
when
configured
with or
without
switch

Dirty Filter, supply fan run time exceeded, filter
switch configuration wrong.

Configure
correctly

More than one binary input is configured for the
same purpose. More then one discrete input is
configured to provide the same function.

Configure
correctly

More then one analog input is configured to
provide the same function.

Automatic

Faulty, shorted, or open thermistor caused by
wiring error or loose connection.

Automatic

Sensor reading is out of range. Bad sensor, bad
wiring, or sensor configured incorrectly.

Switch Configuration
Alarm

sw_cfg_alarm

Misconfigured Analog
Input

an_cfg_alarm

OAT Sensor Alarm

oat_alarm

Space RH Sensor Alarm

sprh_alarm

Outdoor RH Sensor
Alarm

oarh_alarm

Alarm Generated

Automatic

High Space Humidity

sprh_hi

Alarm Generated

Automatic

Low Space Humidity

sprh_lo

Automatic

IAQ Sensor Alarm

iaq_alarm

OAQ Sensor Alarm

oaq_alarm

Alarm Generated
Alarm Generated
Disables IAQ
Operation
Economizer moves
to minimum position
Alarm Generated Set
OAQ to 400

co2_hi

Alarm Generated

sf_rntm

Alarm Generated

dx1_rntm

Alarm Generated

dx2_rntm

Alarm Generated

High Carbon Dioxide
Level
Supply Fan Runtime
Alarm
Compressor 1 Runtime
Alarm
Compressor 2 Runtime
Alarm

PROBABLE CAUSE

Sensor reading is out of range. Bad sensor, bad
wiring, or sensor configured incorrectly.
IRH is greater then 70% for more then 10
minutes.
IRH is less then 35% for more then 10 minutes.

Automatic

Sensor reading is out of range. Bad sensor, bad
wiring, or sensor configured incorrectly.

Automatic

Sensor reading is out of range. Bad sensor, bad
wiring, or sensor configured incorrectly.

Automatic

CO2 reading is above 1200ppm.

clear the
timer
clear the
timer
clear the
timer

53

Supply fan run time exceeded user defined limit.
Compressor run time limit is exceeded.
Compressor run time limit is exceeded.

48TC

POINT NAME

BACnet
OBJECT
NAME

48TC

Alarms
Alarms can be checked through the network and/or the
local access. All the alarms are listed in Table 23 with
name, object name, action taken by control, reset method,
and probable cause. There are help screens for each alarm
on the local access display and listed in RTU-- MP
Controls, Start-- Up, Operation, and Troubleshooting
Instructions (Form 48-- 50H-- T-- 2T), Appendix A: Help
Screens. Some alarms are explained in detail below.
Safety Chain Alarm
This alarm occurs immediately if the supply-- fan internal
overload trips or if an electric-- heat limit switch trips. The
Unit Status will be Shutdown and the System Mode will
be Disable. When this happens LCTB (R terminal) will
not have 24 VAC, but the RTU-- MP board will still be
powered. All unit operations stop immediately and will
not restart until the alarm automatically clears. There are
no configurations for this alarm; it is all based on internal
wiring. This alarm will never occur if Fire Shutdown
Alarm is active.
Fire Shutdown Alarm
This alarm occurs immediately when the smoke detector
senses smoke. The Unit Status will be Shutdown and the
System Mode will be Disable. All unit operations stop
immediately and will not restart until the alarm
automatically clears. If there is not a smoke detector
installed or the smoke detector did not trip, check input
configurations.
Space Temp Sensor Failure
This alarm occurs if the space sensor wired to the
RTU-- MP is disconnected or shorted for more then 10
seconds. When this occurs the Unit Status will be
Shutdown and the System Mode will be Run. Sensor,
sensor connections, wiring, board connection, and
configurations should be checked for faults or errors.
Alarm will reset automatically when cause is fixed.
SAT Sensor Alarm
This alarm occurs immediately when the supply air
temperature sensor wired to the RTU-- MP is disconnected
or shorted. When this occurs the Unit Status will be
Shutdown and the System Mode will be Run. Sensor,
sensor connections, wiring, board connection, and
configurations should be checked for faults or errors.
Alarm will reset automatically when cause is fixed.
Switch Configuration Alarm
This occurs if more than one binary input (inputs 3, 5, 8,
and 9) is configured for the same function. When this
happens the two inputs (or more) configured wrong will
be disabled as an inputs. This alarm will automatically be
cleared when configuration is corrected.
An example of this would be: Input 3 = Compressor
Safety, input 5 = Fan Status, input 8 = Fan Status, and
input 9 = Humidistat; the alarm would be active, unit
would run, compressor safety and humidistat would
function normally, and Fan Status (inputs 5 & 8) will be
interpreted as “No Function.”

Misconfigured Analog Input
This occurs if more than one analog input (inputs 1 & 2)
is configured for the same sensor. When this happens the
two inputs will be disabled as inputs. This alarm will
automatically be cleared when configuration is corrected.
An example of this would be: Input 1 = IAQ Sensor, input
2 = IAQ Sensor; the alarm would be active, unit would
run, but the IAQ Sensor (inputs 1 & 2) will be interpreted
as “No Function.”
Third Party Networking
Third
party
communication
and
networking
troubleshooting should be done by or with assistance from
the front end 3rd party technician. A Module Status
Report (Modstat) can be run from the BACview6, see
Table 24 to perform. This lists information about the
board status and networking state. For basic
troubleshooting, see Table 25. Refer to the RTU-- MP 3rd
Party Integration Guide for additional information.

BACnet MS/TP
1. Verify that the BAS and controller are both set to
speak the BACnet MS/TP protocol. The protocol of
the controller is set via SW3 (switches 3, 4, 5, and 6).
The protocol can also be verified by getting a Modstat
of the controller through the BACview. Hit the “FN”
key and the ’.’ key at the same time to pull up a
Modstat. Scroll to the bottom of the page and there is
a section entitled “Network Communications.” The
active protocol and baud rate will be shown in this
section.
2. Verify that the BAS and controller are set for the
same baud rate. The baud rate of the controller is set
via SW3 (switches 1 and 2). The baud rate can also
be verified via the BACview by obtaining a Modstat.
(See Fig. 70.)
3. Verify that the BAS is configured to speak 2-- wire
EIA-- 485 to the controller. The BAS may have to
configure jumper or DIP switches on their end.
4. Verify that the BAS and the controller have the same
communication settings (8 data bits, No Parity, and 1
stop bit).
5. Verify that the controller has a unique MAC address
on the MS/TP bus. The controller’s MS/TP MAC
address is set by its rotary address switches.
6. Verify proper wiring between the BAS and the
controller.
7. Verify that the BAS is reading or writing to the proper
BACnet objects in the controller. Download the latest
points list for the controller to verify.
8. Verify that the BAS is sending his requests to the
proper MS/TP MAC address of our controller.
9. Present the BAS company with a copy of our
controller’s BACnet PICS so that they know which
BACnet commands are supported. See below.

54

Device Instance: 0160001
1 PRGs loaded.

1 PRGs running.

Module status:
Firmware sections validated in flash memory
============================================
Boot16-H
- v2.06:001
Jun 19 2007
RTU-MP DRIVER
- v2.09:050
Jun 26 2007

System error message history:
Warning message history:
Information message history:
POWERUP: BACnet reinitialize warmstart
Menu file not found.

Type

48TC

Reset counters:
11 Power failures
0 Brownouts
18 Commanded warm boots
22 Commanded cold boots
0 System errors
0 Watchdog timeouts
Specific

06/29/07 10:49:40
06/29/07 10:48:35

ARC156 reconfigurations during the last hour (cleared upon reset):
Total ....................... 0
Initiated by this node ...... 0
Core board hardware:
Type=147, board=34, manufactured on 05/14/2007, S/N 21A740188N
RAM: 1024 kBytes;
FLASH: 1024 kBytes, type = 3
Base board hardware:
Type=147, board=71, manufactured on 05/14/2007, S/N RMP750037N
Largest free heap space = 65536.
Database size = 742082 , used = 352162, free = 389920.
Raw physical switches: 0x01280000
Module Communications:
Network Protocol=BACnet MSTP Master
Network Baud Rate=9600 bps

Fig. 70 - Module Status Report (Modstat) Example
10. In certain situations, it may be necessary to tweak the
MS/TP Protocol timing settings through the
BACview6. There are two settings that may be
tweaked:
S Max Masters: Defines the highest MS/TP Master MAC
address on this MS/TP network. For example, if there are
3 master nodes on an MS/TP network, and their MAC
addresses are 1, 8, and 16, then Max Masters would be set
to 16 (since this is the highest MS/TP MAC address on
the network). This property optimizes MS/TP network
communications by preventing token passes and “poll for
master” requests to non-- existent Master nodes (i.e., in
the above example, MAC address 16 would know to pass
the token back to MAC address 1 instead of counting up
to MAC address 127).
Each MS/TP master node on the network must have their
Max Masters set to this same value. The default is 127.

C07195

S MaxInfo Frames: This property defines the maximum
number of responses that will be sent when our controller
gets the token. A valid number is any positive integer.
The default is 10 and should be ideal for the majority of
applications. In cases where the controller is the target of
many requests, this number could be increased as high as
100 or 200.
NOTE: MS/TP networks can be comprised of both
Master and Slave nodes. Valid MAC addresses for Master
nodes are 0 - 127 and valid addresses for Slave nodes are
0 - 254.
NOTE: See RTU-- MP 3rd Party Integration Guide (or
alternatively RTU-- MP Controls, Start-- Up, Operation, and
Troubleshooting Instructions (Form 48-- 50H-- T-- 2T)
Appendix) for Protocol Maps.

55

48TC

Table 24 – Manufacture Date
When troubleshooting, you may need to know a control module’s manufacture date
Obtain the manufacture date from
a...

Notes

Module status report (modstat)

To obtain a modstat with BACview6:
1. Press Function (FN) key and hold.
2. Then press period (.)
3. Release both buttons.
The report shows the date under Main board hardware.

Sticker on the back of the main control
module board
”Serial No: RMPYMxxxxN”
(Bar Coded & Typed Number)

The serial numbers are unique and contain embedded information:
“RMP”
--These first three digits are unique to RTU--- MP and are used as an identifier.
“YM”
--These two digits identify the last digit of the year and month (in hex, A=10/Oct)
of manufacture. ”74” would represent a date of manufacture of ”April 2007”.
“xxxx”
--These four digits represent the sequential number of units produced for a given
product for the mentioned manufacturing time period.
“N”
--This final digit represents the decade and toggles between ”N” and ”M” every
ten years.

Table 25 – Basic Protocol Troubleshooting
Problem
No communication with 3rd
party vendor

Possible cause
Incorrect settings on SW1, SW2 and SW3
RS485 Port has no voltage output
(check with RTU--- MP disconnected from RS485
communication bus)
Bacnet @ 9600/19.2K --- .01 to .045vdc
Bacnet @ 38.4K --- .06 to .09vdc
Bacnet @ 76.8K --- .1vdc
Modbus @ 9600 --- 76.8K --- .124vdc
N2 @ 9600 --- .124vdc
Verify devices are daisy chained and repeaters and bias
terminators are correctly installed

Table 26 – Modbus Exception Codes that May be
Returned From This Controller
CODE

NAME

MEANING

01

Illegal Function

The Modbus function code used
in the query is not supported by
the controller.

02

Illegal Data Address

The register address used in the
query is not supported by the
controller.

Slave Device Failure

The Modbus Master has
attempted to write to a
non--- existent register or a
read --- only register in the
controller.

04

Corrective action
Verify and correct switch settings. Cycle
power to RTU--- MP after changing switch
settings.
Verify RTU--- MP has correct power supply
Possible bad driver on board.
Check RS485 bus for external before
reconnecting to the bus
Voltage, shorts or grounding
before reconnecting to the bus

Check 3rd party vendor RS485
communication wiring guidelines and
troubleshooting procedures

2. Verify that the BAS and controller are set for the
same baud rate. The baud rate of the controller is set
via SW3 (switches 1 and 2). The baud rate can also
be verified via the BACview by obtaining a Modstat
(see Fig. 70).
3. Verify that the BAS is configured to speak 2-- wire
EIA-- 485 to the controller. The BAS may have to
configure jumper or DIP switches on their end.
4. Verify that the BAS and the controller have the same
communication settings (8 data bits, No Parity, and 1
stop bit).
5. Verify that the controller has a unique Modbus slave
address. The controller’s Modbus slave address is set
by its rotary address switches.
6. Verify that the BAS is using the proper Modbus
function codes to access data from our controller.
Supported function codes are shown above.
7. Verify proper wiring between the BAS and the
controller.
8. Verify that the BAS is reading or writing to the proper
Modbus register numbers on the controller. Download
the latest points list for the controller to verify.
9. Verify that the BAS is sending his requests to the
proper slave address of our controller.

Modbus
1. Verify that the BAS and controller are both set to
speak the Modbus RTU protocol. The protocol of the
controller is set via SW3 (switches 3, 4, 5, and 6).
The protocol can also be verified by getting a Modstat
of the controller through the BACview. Hit the ”FN”
key and the ’.’ key at the same time to pull up a
Modstat. Scroll to the bottom of the page and there is
a section entitled “Network Communications.” The
active protocol and baud rate will be shown in this
section.

56

N2
1. Verify that the BAS and controller are both set to
speak the N2 protocol. The protocol of the controller
is set via SW3 (switches 3, 4, 5, and 6). The protocol
can also be verified by getting a Modstat of the
controller through the BACview. Hit the “FN” key
and the ’.’ key at the same time to pull up a Modstat.
Scroll to the bottom of the page and there is a section
entitled ”Network Communications.” The active
protocol and baud rate will be shown in this section.
2. Verify that the BAS and controller are set for 9600
baud. The baud rate of the controller is set via SW3
(switches 1 and 2). The baud rate can also be verified
via the BACview by obtaining a Modstat. (See Fig.
70.)
3. Verify that the BAS is configured to speak 2-- wire
EIA-- 485 to the controller. The BAS may have to
configure jumper or DIP switches on their end.
4. Verify that the BAS and the controller have the same
communication settings (8 data bits, No Parity, and 1
stop bit).
5. Verify that the controller has a unique N2 slave
address on the N2 bus. The controller’s N2 slave
address is set by its rotary address switches.
6. Verify proper wiring between the BAS and the
controller.
7. Verify that the BAS is reading or writing to the proper
network point addresses on the controller. Download
the latest points list for the controller to verify.
8. Verify that the BAS is sending his requests to the
proper slave address of our controller.
NOTE: See RTU-- MP 3rd Party Integration Guide (or
alternatively RTU-- MP 3rd Party Integration Guide (or
alternatively RTU-- MP Controls, Start-- Up, Operation, and
Troubleshooting Instructions (Form 48-- 50H-- T-- 2T)
Appendix) for N2 Protocol Conformance Statement.

ECONOMI$ER SYSTEMS
The 48TC units may be equipped with a factory-- installed
or accessory (field-- installed) economizer system. Two
types are available: with a logic control system
(EconoMi$er IV) and without a control system
(EconoMi$er2, for use with external control systems such
as PremierLink). See Fig. 71 and Fig. 72 for component
locations on each type. See Fig. 73 and Fig. 74 for
economizer section wiring diagrams.
Both EconoMi$ers use direct-- drive damper actuators.
ECONOMI$ER IV
CONTROLLER
WIRING
HARNESS
ACTUATOR
(HIDDEN)

48TC

NOTE: See RTU-- MP 3rd Party Integration Guide (or
alternatively RTU-- MP 3rd Party Integration Guide (or
alternatively RTU-- MP Controls, Start-- Up, Operation, and
Troubleshooting Instructions (Form 48-- 50H-- T-- 2T),
Appendix) for Modbus Protocol Conformance Statement.

LOW TEMPERATURE
COMPRESSOR
LOCKOUT SWITCH
OUTSIDE AIR
TEMPERATURE SENSOR
(OPERATING LOCATION)
C07367

Fig. 71 - EconoMi$er IV Component Locations
OUTDOOR
AIR HOOD

ECONOMI$ER2
PLUG

BAROMETRIC
RELIEF
DAMPER

HOOD
SHIPPING
BRACKET

GEAR DRIVEN
DAMPER

C06022

Fig. 72 - EconoMi$er2 Component Locations

57

48TC

C09023

Fig. 73 - EconoMi$er IV Wiring

BLACK

4

TRANSFORMER
GROUND

3
5
BLUE
500 OHM
RESISTOR

2
8

VIOLET

6

NOTE 1
PINK

7

RUN
OAT SENSOR

RED

NOTE 3

1

24 VAC

10
YELLOW

50HJ540573
ACTUATOR
ASSEMBLY

11
9

DIRECT DRIVE
ACTUATOR

4-20mA SIGNAL

WHITE

12

4-20 mA
TO J9 ON
PremierLink
BOARD

ECONOMISER2 PLUG

NOTES:
1. Switch on actuator must be in run position for economizer to operate.
2. PremierLink™ control requires that the standard 50HJ540569 outside-air sensor be replaced by either the CROASENR001A00 dry bulb sen
sor or HH57A077 enthalpy sensor.
3. 50HJ540573 actuator consists of the 50HJ540567 actuator and a harness with 500-ohm resistor.

Fig. 74 - EconoMi$er2 with 4 to 20 mA Control Wiring

58

C08310

Table 27 – EconoMi$er IV Input/Output Logic

Below set
(DCV LED Off)

Above set
(DCV LED On)

Outdoor

Return

High
(Free Cooling LED
Off)

Low

Low
(Free Cooling LED
On)

High

High
(Free Cooling LED
Off)

Low

Low
(Free Cooling LED
On)

High

On
On
Off

Compressor
Y2 Stage Stage
1
2
On
On
On
Off
On
Off
Off
Off
Off

On

On

On

Off

On

Off

Off

Off

Off
On

Off
On

Off
On

Off
On

On

Off

On

Off

Off
On
On
Off

Off
On
Off
Off

Off
On
Off
Off

Off
Off
Off
Off

Y1

OUTPUTS
N Terminal†
Occupied
Unoccupied
Damper
Minimum position

Closed

Modulating** (between
min. position and
full-open)
Minimum position

Modulating**
(between closed and
full-open)
Closed
Modulating††
(between closed and
DCV
maximum)

Modulating†† (between
min. position and DCV
maximum)
Modulating***

Modulating†††

*
†
**
††
***

For single enthalpy control, the module compares outdoor enthalpy to the ABCD setpoint.
Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), no power (Unoccupied).
Modulation is based on the supply-air sensor signal.
Modulation is based on the DCV signal.
Modulation is based on the greater of DCV and supply-air sensor signals, between minimum position and either maximum position (DCV)
or fully open (supply-air signal).
††† Modulation is based on the greater of DCV and supply-air sensor signals, between closed and either maximum position (DCV) or fully
open (supply-air signal).

Fig. 75 - EconoMi$er IV Functional View

C06053

EconoMi$er IV

EconoMi$er IV Standard Sensors

Table 27 provides a summary of EconoMi$er IV.
Troubleshooting instructions are enclosed.

Outdoor Air Temperature (OAT) Sensor
The outdoor air temperature sensor (HH57AC074) is a 10
to 20 mA device used to measure the outdoor-air
temperature. The outdoor-air temperature is used to
determine when the EconoMi$er IV can be used for free
cooling. The sensor is factory-installed on the
EconoMi$er IV in the outdoor airstream. (See Fig. 71.)
The operating range of temperature measurement is 40_ to
100_F (4_ to 38_C). (See Fig. 78.)

A functional view of the EconoMi$er is shown in Fig. 75.
Typical settings, sensor ranges, and jumper positions are
also shown. An EconoMi$er IV simulator program is
available from Carrier to help with EconoMi$er IV
training and troubleshooting.

59

48TC

Demand Control
Ventilation (DCV)

INPUTS
Enthalpy*

Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a 3 K thermistor
located at the inlet of the indoor fan. (See Fig. 76.) This
sensor is factory installed. The operating range of
temperature measurement is 0° to 158_F (-- 18_ to 70_C).
See Table 15 for sensor temperature/resistance values.

The scale on the potentiometer is A, B, C, and D. See Fig.
74 for the corresponding temperature changeover values.

SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION

48TC

SUPPLY AIR
TEMPERATURE
SENSOR

Fig. 76 - Supply Air Sensor Location

C06033
C06034

Fig. 77 - EconoMi$er IV Controller Potentiometer
and LED Locations

The temperature sensor looks like an eyelet terminal with
wires running to it. The sensor is located in the “crimp
end” and is sealed from moisture.
Outdoor Air Lockout Sensor
The EconoMi$er IV is equipped with an ambient
temperature lockout switch located in the outdoor
airstream which is used to lock out the compressors below
a 42_F (6_C) ambient temperature. (See Fig. 71.)
EconoMi$er IV Control Modes
IMPORTANT: The optional EconoMi$er2 does not
include a controller. The EconoMi$er2 is operated by a 4
to 20 mA signal from an existing field-supplied controller
(such as PremierLink™ control). See Fig. 74 for wiring
information.
Determine the EconoMi$er IV control mode before set up
of the control. Some modes of operation may require
different sensors. (See Table 27.) The EconoMi$er IV is
supplied from the factory with a supply-air temperature
sensor and an outdoor-air temperature sensor. This allows
for operation of the EconoMi$er IV with outdoor air dry
bulb changeover control. Additional accessories can be
added to allow for different types of changeover control
and operation of the EconoMi$er IV and unit.
Outdoor Dry Bulb Changeover
The standard controller is shipped from the factory
configured for outdoor dry bulb changeover control. The
outdoor air and supply air temperature sensors are
included as standard. For this control mode, the outdoor
temperature is compared to an adjustable setpoint selected
on the control. If the outdoor-air temperature is above the
setpoint, the EconoMi$er IV will adjust the outside air
dampers to minimum position. If the outdoor-air
temperature is below the setpoint, the position of the
outside air dampers will be controlled to provided free
cooling using outdoor air. When in this mode, the LED
next to the free cooling setpoint potentiometer will be on.
The changeover temperature setpoint is controlled by the
free cooling setpoint potentiometer located on the control.
(See Fig. 77.)

19
LED ON

18

D

17

LED OFF

16

LED ON

C

mA

15
14

LED OFF

13
12

LED ON

B

LED OFF

LED ON

A

11
10

LED OFF

9
40

45

50

55

60
65 70 75 80
DEGREES FAHRENHEIT

85

90

100

95

C06035

FLOW IN CUBIC FEET PER MINUTE (cfm)

Fig. 78 - Outside Air Temperature Changeover
Setpoints

30
25
20
15
10
5
0

0.13

0.20 0.22

0.25

0.30 0.35 0.40

0.45

0.50

STATIC PRESSURE (in. wg)

Fig. 79 - Outdoor-- Air Damper Leakage

60

C06031

In this mode of operation, the outdoor-air temperature is
compared to the return-air temperature and the lower
temperature airstream is used for cooling. When using this
mode of changeover control, turn the enthalpy setpoint
potentiometer fully clockwise to the D setting. (See Fig.
77.)
Outdoor Enthalpy Changeover
For enthalpy control, accessory enthalpy sensor (part
number HH57AC078) is required. Replace the standard
outdoor dry bulb temperature sensor with the accessory
enthalpy sensor in the same mounting location. (See Fig.
80.) When the outdoor air enthalpy rises above the
outdoor enthalpy changeover setpoint, the outdoor-air
damper moves to its minimum position. The outdoor
enthalpy changeover setpoint is set with the outdoor
enthalpy setpoint potentiometer on the EconoMi$er IV
controller. The setpoints are A, B, C, and D. (See Fig. 81.)
The factory-installed 620-ohm jumper must be in place
across terminals SR and SR+ on the EconoMi$er IV
controller.

ECONOMI$ERIV
CONTROLLER

ECONOMI$ERIV

GROMMET

RETURN AIR
SENSOR

RETURN DUCT
(FIELD-PROVIDED)
C07085

Fig. 80 - Return Air Temperature or Enthalpy Sensor
Mounting Location

46

85
90
95 100 105 110
(29) (32) (35) (38) (41) (43)

44

CONTROL CONTROL POINT
CURVE
APPROX. deg. F (deg. C)

80
(27)

42

AT 50% RH

)
IDI
LA
RE
80

20

50

60
(16)

A

40

22

60

70

24

65
(18)

10
0
90

28

26

EN

UM
EH
TIV

R
PE
U

32

30

70
(21)

TH

AL

PY

BT

75
(24)

34

PO

UN

TY

38

(%

RY

AI

40

R

73 (23)
70 (21)
67 (19)
63 (17)

36 D D

16

18

55
(13) B

14

50
(10)

12

45
(7)

30

A
B
C
D

C

20

D

40
(4)

10

35
(2)

B A
D C
35
(2)

40
(4)

45
(7)

50
(10)

55
60
70
65
75
80
85
90
95 100 105 110
(13) (16) (18) (21) (24) (27) (29) (32) (35) (38) (41) (43)

HIGH LIMIT
CURVE

APPROXIMATE DRY BULB TEMPERATURE--degrees F (degrees C)

Fig. 81 - Enthalpy Changeover Setpoints

61

C06037

48TC

Differential Dry Bulb Control
For differential dry bulb control the standard outdoor dry
bulb sensor is used in conjunction with an additional
accessory
dry
bulb
sensor
(part
number
CRTEMPSN002A00). The accessory sensor must be
mounted in the return airstream. (See Fig. 80.) Wiring is
provided in the EconoMi$er IV wiring harness. (See Fig.
73.)

EXH

N1

P

Min
Pos

T1

DCV
2V

AQ

SO

48TC

SR

+

_

Max
10V

1

2

CO2 SENSOR MAX RANGE SETTING
6000

5

DCV

SO+

SR+

24 Vac
COM

Open

T

AQ1

24
Vac
HOT

Adjust the DCV potentiometers to correspond to the DCV
voltage output of the indoor air quality sensor at the
user-determined setpoint. (See Fig. 83.)

Set
10V

2V
EXH

P1

TR1

RANGE CONFIGURATION (ppm)

N

TR

2V

DCV
Set
10V

Free
Cool
B

C

A

D

3

4

EF

EF1

5000
4000

800 ppm
900 ppm
1000 ppm
1100 ppm

3000
2000
1000
0
2

3

4

5

6

7

8

DAMPER VOLTAGE FOR MAX VENTILATION RATE

Fig. 82 - EconoMi$er IV Control

C06038

Differential Enthalpy Control
For differential enthalpy control, the EconoMi$er IV
controller uses two enthalpy sensors (HH57AC078 and
CRENTDIF004A00), one in the outside air and one in the
return air duct. The EconoMi$er IV controller compares
the outdoor air enthalpy to the return air enthalpy to
determine EconoMi$er IV use. The controller selects the
lower enthalpy air (return or outdoor) for cooling. For
example, when the outdoor air has a lower enthalpy than
the return air, the EconoMi$er IV opens to bring in
outdoor air for free cooling.
Replace the standard outside air dry bulb temperature
sensor with the accessory enthalpy sensor in the same
mounting location. (See Fig. 71.) Mount the return air
enthalpy sensor in the return air duct. (See Fig. 80.)
Wiring is provided in the EconoMi$er IV wiring harness.
(See Fig. 73.) The outdoor enthalpy changeover setpoint is
set with the outdoor enthalpy setpoint potentiometer on
the EconoMi$er IV controller. When using this mode of
changeover control, turn the enthalpy setpoint
potentiometer fully clockwise to the D setting.
Indoor Air Quality (IAQ) Sensor Input
The IAQ input can be used for demand control ventilation
control based on the level of CO2 measured in the space
or return air duct.
There is both a factory-installed (FIOP) CO2 option
(sensor 8001B with no display, which is mounted on the
side of the EconoMi$er) and a field-installed CO2 option
(sensor 8002 with display, which is mounted on the return
air duct). While performing the same function, they differ
in their ability to be configured. The FIOP version is
preset and requires no changes in most applications. If a
configuration change is required, service kit #UIP2072
(software CD, cables, and instructions) and a laptop PC
are required. The field-installed version with display can
be configured stand-alone. (See section “CO2 Sensor
Configuration”.)
Mount the accessory IAQ sensor according to
manufacturer specifications. The IAQ sensor should be
wired to the AQ and AQ1 terminals of the controller.

C06039

Fig. 83 - CO2 Sensor Maximum Range Settings

If a separate field-supplied transformer is used to power
the IAQ sensor, the sensor must not be grounded or the
EconoMi$er IV control board will be damaged.
When using demand ventilation, the minimum damper
position represents the minimum ventilation position for
VOC (volatile
organic
compounds)
ventilation
requirements. The maximum demand ventilation position
is used for fully occupied ventilation.
When demand ventilation control is not being used, the
minimum position potentiometer should be used to set the
occupied ventilation position. The maximum demand
ventilation position should be turned fully clockwise.
Exhaust Setpoint Adjustment
The exhaust setpoint will determine when the exhaust fan
runs based on damper position (if accessory power
exhaust is installed). The setpoint is modified with the
Exhaust Fan Setpoint (EXH SET) potentiometer. (See Fig.
77.) The setpoint represents the damper position above
which the exhaust fans will be turned on. When there is a
call for exhaust, the EconoMi$er IV controller provides a
45 ± 15 second delay before exhaust fan activation to
allow the dampers to open. This delay allows the damper
to reach the appropriate position to avoid unnecessary fan
overload.
Minimum Position Control
There is a minimum damper position potentiometer on the
EconoMi$er IV controller. (See Fig. 77.) The minimum
damper position maintains the minimum airflow into the
building during the occupied period.
When using demand ventilation, the minimum damper
position represents the minimum ventilation position for
VOC
(volatile
organic
compound)
ventilation
requirements. The maximum demand ventilation position
is used for fully occupied ventilation.
When demand ventilation control is not being used, the
minimum position potentiometer should be used to set the
occupied ventilation position. The maximum demand
ventilation position should be turned fully clockwise.

62

(TO x

OA + (TR
)
100

x

RA
) =TM
100

TO = Outdoor-Air Temperature
OA = Percent of Outdoor Air
TR = Return-Air Temperature
RA = Percent of Return Air
TM = Mixed-Air Temperature
As an example, if local codes require 10% outdoor
air during occupied conditions, outdoor-air
temperature is 60_F, and return-air temperature is
75_F.
(60 x .10) + (75 x .90) = 73.5_F
2. Disconnect the supply air sensor from terminals T
and T1.
3. Ensure that the factory-installed jumper is in place
across terminals P and P1. If remote damper
positioning is being used, make sure that the
terminals are wired according to Fig. 73 and that the
minimum position potentiometer is turned fully
clockwise.
4. Connect 24 vac across terminals TR and TR1.
5. Carefully
adjust
the
minimum
position
potentiometer until the measured mixed air
temperature matches the calculated value.
6. Reconnect the supply air sensor to terminals T and
T1.
Remote control of the EconoMi$er IV damper is desirable
when requiring additional temporary ventilation. If a
field-supplied remote potentiometer (Honeywell part
number S963B1128) is wired to the EconoMi$er IV
controller, the minimum position of the damper can be
controlled from a remote location.
To control the minimum damper position remotely,
remove the factory-installed jumper on the P and P1
terminals on the EconoMi$er IV controller. Wire the
field-supplied potentiometer to the P and P1 terminals on
the EconoMi$er IV controller. (See Fig. 73.)
Damper Movement
Damper movement from full open to full closed (or vice
versa) takes 2-1/2 minutes.

Thermostats
The EconoMi$er IV control works with conventional
thermostats that have a Y1 (cool stage 1), Y2 (cool stage
2), W1 (heat stage 1), W2 (heat stage 2), and G (fan). The
EconoMi$er IV control does not support space
temperature sensors. Connections are made at the
thermostat terminal connection board located in the main
control box.
Demand Control Ventilation (DCV)
When using the EconoMi$er IV for demand controlled
ventilation, there are some equipment selection criteria
which should be considered. When selecting the heat
capacity and cool capacity of the equipment, the
maximum ventilation rate must be evaluated for design
conditions. The maximum damper position must be
calculated to provide the desired fresh air.
Typically the maximum ventilation rate will be about 5 to
10% more than the typical cfm required per person, using
normal outside air design criteria.
A proportional anticipatory strategy should be taken with
the following conditions: a zone with a large area, varied
occupancy, and equipment that cannot exceed the required
ventilation rate at design conditions. Exceeding the
required ventilation rate means the equipment can
condition air at a maximum ventilation rate that is greater
than the required ventilation rate for maximum
occupancy. A proportional-anticipatory strategy will cause
the fresh air supplied to increase as the room CO2 level
increases even though the CO2 setpoint has not been
reached. By the time the CO2 level reaches the setpoint,
the damper will be at maximum ventilation and should
maintain the setpoint.
In order to have the CO2 sensor control the economizer
damper in this manner, first determine the damper voltage
output for minimum or base ventilation. Base ventilation
is the ventilation required to remove contaminants during
unoccupied periods. The following equation may be used
to determine the percent of outside air entering the
building for a given damper position. For best results there
should be at least a 10 degree difference in outside and
return-air temperatures.
(TO x

OA + (TR
)
100

x

RA
) =TM
100

TO = Outdoor-Air Temperature
OA = Percent of Outdoor Air
TR = Return-Air Temperature
RA = Percent of Return Air
TM = Mixed-Air Temperature
Once base ventilation has been determined, set the
minimum damper position potentiometer to the correct
position.

63

48TC

Adjust the minimum position potentiometer to allow the
minimum amount of outdoor air, as required by local
codes, to enter the building. Make minimum position
adjustments with at least 10_F temperature difference
between the outdoor and return-air temperatures.
To determine the minimum position setting, perform the
following procedure:
1. Calculate the appropriate mixed air temperature
using the following formula:

48TC

The same equation can be used to determine the occupied
or maximum ventilation rate to the building. For example,
an output of 3.6 volts to the actuator provides a base
ventilation rate of 5% and an output of 6.7 volts provides
the maximum ventilation rate of 20% (or base plus 15 cfm
per person). Use Fig. 83 to determine the maximum
setting of the CO2 sensor. For example, an 1100 ppm
setpoint relates to a 15 cfm per person design. Use the
1100 ppm curve on Fig. 83 to find the point when the CO2
sensor output will be 6.7 volts. Line up the point on the
graph with the left side of the chart to determine that the
range configuration for the CO2 sensor should be 1800
ppm. The EconoMi$er IV controller will output the 6.7
volts from the CO2 sensor to the actuator when the CO2
concentration in the space is at 1100 ppm. The DCV
setpoint may be left at 2 volts since the CO2 sensor
voltage will be ignored by the EconoMi$er IV controller
until it rises above the 3.6 volt setting of the minimum
position potentiometer.

Once the fully occupied damper position has been
determined, set the maximum damper demand control
ventilation potentiometer to this position. Do not set to the
maximum position as this can result in over-ventilation to
the space and potential high humidity levels.
CO2 Sensor Configuration
The CO2 sensor has preset standard voltage settings that
can be selected anytime after the sensor is powered up.
(See Table 28.)
Use setting 1 or 2 for Carrier equipment. (See Table 28.)
1. Press Clear and Mode buttons. Hold at least 5
seconds until the sensor enters the Edit mode.
2. Press Mode twice. The STDSET Menu will appear.

Table 28 – CO2 Sensor Standard Settings
OUTPUT

VENTILATION
RATE
(cmf/Person)

ANALOG
OUTPUT

CO2
CONTROL
RANGE
(ppm)

OPTIONAL
RELAY SETPOINT
(ppm)

RELAY
HYSTERESIS
(ppm)

Proportional

Any

0--- 10V
4--- 20mA

0--- 2000

1000

50

Proportional

Any

2--- 10V
7--- 20mA

0--- 2000

1000

50

3

Exponential

Any

0--- 10V
4--- 20mA

0--- 2000

1100

50

4

Proportional

15

0--- 10V
4--- 20mA

0--- 1100

1100

50

5

Proportional

20

0--- 10V
4--- 20mA

0--- 900

900

50

6

Exponential

15

0--- 10V
4--- 20mA

0--- 1100

1100

50

7

Exponential

20

0--- 10V
4--- 20mA

0--- 900

900

50

SETTING

EQUIPMENT

1
2

Interface w/Standard
Building Control System

Economizer

8

Health & Safety

Proportional

—

0--- 10V
4--- 20mA

0--- 9999

5000

500

9

Parking/Air Intakes/
Loading Docks

Proportional

—

0--- 10V
4--- 20mA

0--- 2000

700

50

64

APPLICATION
Outdoor Air
Dry Bulb
Differential
Dry Bulb
Single Enthalpy
Differential
Enthalpy
CO2 for DCV
Control using a
Wall-Mounted
CO2 Sensor
CO2 for DCV
Control using a
Duct-Mounted
CO2 Sensor

ECONOMI$ER IV WITH OUTDOOR AIR DRY
BULB SENSOR
Accessories Required
None. The outdoor air dry bulb sensor is
factory installed.
CRTEMPSN002A00*
HH57AC078
HH57AC078 and CRENTDIF004A00*
33ZCSENCO2

33ZCSENCO2† and O
CRCBDIOX005A00††
33ZCASPCO2**
R

* CRENTDIF004A00 and CRTEMPSN002A00 accessories are
used on many different base units. As such, these kits may
contain parts that will not be needed for installation.
† 33ZCSENCO2 is an accessory CO2 sensor.
** 33ZCASPCO2 is an accessory aspirator box required for
duct-mounted applications.
†† CRCBDIOX005A00 is an accessory that contains both
33ZCSENCO2 and 33ZCASPCO2 accessories.

3. Use the Up/Down button to select the preset
number. (See Table 28.)
4. Press Enter to lock in the selection.
5. Press Mode to exit and resume normal operation.
The custom settings of the CO2 sensor can be changed
anytime after the sensor is energized. Follow the steps
below to change the non-standard settings:
1. Press Clear and Mode buttons. Hold at least 5
seconds until the sensor enters the Edit mode.
2. Press Mode twice. The STDSET Menu will appear.
3. Use the Up/Down button to toggle to the NONSTD
menu and press Enter.
4. Use the Up/Down button to toggle through each of
the nine variables, starting with Altitude, until the
desired setting is reached.
5. Press Mode to move through the variables.
6. Press Enter to lock in the selection, then press Mode
to continue to the next variable.
Dehumidification of Fresh Air with DCV (Demand
Controlled Ventilation) Control
If normal rooftop heating and cooling operation is not
adequate for the outdoor humidity level, an energy
recovery unit and/or a dehumidification option should be
considered.
EconoMi$er IV Preparation

1. Disconnect power at TR and TR1. All LEDs should
be off. Exhaust fan contacts should be open.
2. Disconnect device at P and P1.
3. Jumper P to P1.
4. Disconnect wires at T and T1. Place 5.6 kilo-- ohm
resistor across T and T1.
5. Jumper TR to 1.
6. Jumper TR to N.
7. If connected, remove sensor from terminals SO and +.
Connect 1.2 kilo-- ohm 4074EJM checkout resistor
across terminals SO and +.
8. Put 620-- ohm resistor across terminals SR and +.
9. Set minimum position, DCV setpoint, and exhaust
potentiometers fully CCW (counterclockwise).
10. Set DCV maximum position potentiometer fully CW
(clockwise).
11. Set enthalpy potentiometer to D.
12. Apply power (24 vac) to terminals TR and TR1.
Differential Enthalpy
To check differential enthalpy:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Place 620-- ohm resistor across SO and +.
3. Place 1.2 kilo-- ohm resistor across SR and +. The
Free Cool LED should be lit.
4. Remove 620-- ohm resistor across SO and +. The Free
Cool LED should turn off.
5. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
Single Enthalpy
To check single enthalpy:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Set the enthalpy potentiometer to A (fully CCW). The
Free Cool LED should be lit.
3. Set the enthalpy potentiometer to D (fully CW). The
Free Cool LED should turn off.
4. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
DCV (Demand Controlled Ventilation) and Power
Exhaust
To check DCV and Power Exhaust:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Ensure terminals AQ and AQ1 are open. The LED for
both DCV and Exhaust should be off. The actuator
should be fully closed.
3. Connect a 9-- v battery to AQ (positive node) and AQ1
(negative node). The LED for both DCV and Exhaust
should turn on. The actuator should drive to between
90 and 95% open.
4. Turn the Exhaust potentiometer CW until the Exhaust
LED turns off. The LED should turn off when the
potentiometer is approximately 90%. The actuator
should remain in position.

This procedure is used to prepare the EconoMi$er IV for
troubleshooting. No troubleshooting or testing is done by
performing the following procedure.
NOTE: This procedure requires a 9-- v battery, 1.2
kilo-- ohm resistor, and a 5.6 kilo-- ohm resistor which are
not supplied with the EconoMi$er IV.
IMPORTANT: Be sure to record the positions of all
potentiometers before starting troubleshooting.
65

48TC

Table 29 – EconoMi$er IV Sensor Usage

5. Turn the DCV setpoint potentiometer CW until the
DCV LED turns off. The DCV LED should turn off
when the potentiometer is approximately 9-- v. The
actuator should drive fully closed.
6. Turn the DCV and Exhaust potentiometers CCW until
the Exhaust LED turns on. The exhaust contacts will
close 30 to 120 seconds after the Exhaust LED turns
on.
7. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
DCV Minimum and Maximum Position

48TC

To check the DCV minimum and maximum position:
1. Make sure EconoMi$er IV preparation procedure has
been performed.
2. Connect a 9-- v battery to AQ (positive node) and AQ1
(negative node). The DCV LED should turn on. The
actuator should drive to between 90 and 95% open.
3. Turn the DCV Maximum Position potentiometer to
midpoint. The actuator should drive to between 20
and 80% open.
4. Turn the DCV Maximum Position potentiometer to
fully CCW. The actuator should drive fully closed.
5. Turn the Minimum Position potentiometer to
midpoint. The actuator should drive to between 20
and 80% open.
6. Turn the Minimum Position Potentiometer fully CW.
The actuator should drive fully open.
7. Remove the jumper from TR and N. The actuator
should drive fully closed.
8. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
Supply-- Air Sensor Input
To check supply-- air sensor input:
1. Make sure EconoMi$er IV preparation procedure has
been performed.

2. Set the Enthalpy potentiometer to A. The Free Cool
LED turns on. The actuator should drive to between
20 and 80% open.
3. Remove the 5.6 kilo-- ohm resistor and jumper T to
T1. The actuator should drive fully open.
4. Remove the jumper across T and T1. The actuator
should drive fully closed.
5. Return EconoMi$er IV settings and wiring to normal
after completing troubleshooting.
EconoMi$er IV Troubleshooting Completion
This procedure is used to return the EconoMi$er IV to
operation. No troubleshooting or testing is done by
performing the following procedure.
1. Disconnect power at TR and TR1.
2. Set enthalpy potentiometer to previous setting.
3. Set DCV maximum position potentiometer to
previous setting.
4. Set minimum position, DCV setpoint, and exhaust
potentiometers to previous settings.
5. Remove 620-- ohm resistor from terminals SR and +.
6. Remove 1.2 kilo-- ohm checkout resistor from
terminals SO and +. If used, reconnect sensor from
terminals SO and +.
7. Remove jumper from TR to N.
8. Remove jumper from TR to 1.
9. Remove 5.6 kilo-- ohm resistor from T and T1.
Reconnect wires at T and T1.
10. Remove jumper from P to P1. Reconnect device at P
and P1.
11. Apply power (24 vac) to terminals TR and TR1.

WIRING DIAGRAMS
See Fig. 84 and 85 for typical wiring diagrams.

66

48TC
Fig. 84 - 48TC Typical Unit Wiring Diagram - Power (D08, 208/230-- 3-- 60)

67

C09156

68

Fig. 85 - 48TC Typical Unit Wiring Diagram - Control (D08, 208/230-- 3-- 60)

48TC

C09157

PRE--START--UP

WARNING

PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could result in personal
injury or death.
Relieve pressure and recover all refrigerant before
system repair or final unit disposal.
Wear safety glasses and gloves when handling
refrigerants.
Keep torches and other ignition sources away from
refrigerants and oils.

PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal
injury or death.
1. Follow recognized safety practices and wear
protective goggles when checking or servicing
refrigerant system.
2. Do not operate compressor or provide any electric
power to unit unless compressor terminal cover is
in place and secured.
3. Do not remove compressor terminal cover until
all electrical sources are disconnected.
4. Relieve all pressure from system before touching
or disturbing anything inside terminal box if
refrigerant leak is suspected around compressor
terminals.
5. Never attempt to repair soldered connection while
refrigerant system is under pressure.
6. Do not use torch to remove any component.
System contains oil and refrigerant under
pressure. To remove a component, wear
protective goggles and proceed as follows:
a. Shut off electrical power and then gas to unit.
b. Recover refrigerant to relieve all pressure from
system using both high-- pressure and low
pressure ports.
c. Cut component connection tubing with tubing
cutter and remove component from unit.
d. Carefully unsweat remaining tubing stubs
when necessary. Oil can ignite when exposed
to torch flame.

!

3. Make the following inspections:
a. Inspect for shipping and handling damages such
as broken lines, loose parts, or disconnected
wires, etc.
b. Inspect for oil at all refrigerant tubing
connections and on unit base. Detecting oil
generally indicates a refrigerant leak. Leak-- test
all refrigerant tubing connections using
electronic leak detector, halide torch, or
liquid-- soap solution.
c. Inspect all field-- wiring and factory-- wiring
connections. Be sure that connections are
completed and tight. Be sure that wires are not
in contact with refrigerant tubing or sharp edges.
d. Inspect coil fins. If damaged during shipping and
handling, carefully straighten fins with a fin
comb.
4. Verify the following conditions:
a. Make sure that condenser-- fan blade are correctly
positioned in fan orifice. See Condenser-- Fan
Adjustment section for more details.
b. Make sure that air filter(s) is in place.
c. Make sure that condensate drain trap is filled
with water to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose
parts have been removed.

WARNING

ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
The unit must be electrically grounded in accordance
with local codes and NEC ANSI/NFPA 70 (American
National Standards Institute/National Fire Protection
Association.)
Proceed as follows to inspect and prepare the unit for
initial start-- up:
1. Remove all access panels.
2. Read and follow instructions on all WARNING,
CAUTION, and INFORMATION labels attached to,
or shipped with, unit.

WARNING

START--UP, GENERAL
Unit Preparation
Make sure that unit has been installed in accordance with
installation instructions and applicable codes.

Gas Piping
Check gas piping for leaks.

69

48TC

!

!

!

WARNING

48TC

UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect gas piping from unit when leak testing at
pressure greater than 1/2 psig. Pressures greater than
1/2 psig will cause gas valve damage resulting in
hazardous condition. If gas valve is subjected to
pressure greater than 1/2 psig, it must be replaced
before use. When pressure testing field-- supplied gas
piping at pressures of 1/2 psig or less, a unit connected
to such piping must be isolated by manually closing
the gas valve.

Return--Air Filters

NOTE: When the compressor is rotating in the wrong
direction, the unit will make an elevated level of noise
and will not provide cooling.

Cooling
Set space thermostat to OFF position. To start unit, turn on
main power supply. Set system selector switch at COOL
position and fan switch at AUTO. position. Adjust
thermostat to a setting approximately 5_F (3_C) below
room temperature. Both compressors start on closure of
contactors.
Check unit charge. Refer to Refrigerant Charge section.
Reset thermostat at a position above room temperature.
Both compressors will shut off. Evaporator fan will shut
off immediately.

Make sure correct filters are installed in unit (see
Appendix II - Physical Data). Do not operate unit without
return-- air filters.

To shut off unit, set system selector switch at OFF
position. Resetting thermostat at a position above room
temperature shuts unit off temporarily until space
temperature exceeds thermostat setting.

Outdoor--Air Inlet Screens

Main Burners

Outdoor-- air inlet screen must be in place before operating
unit.

Main burners are factory set and should require no
adjustment.

Compressor Mounting

To check ignition of main burners and heating controls,
move thermostat setpoint above room temperature and
verify that the burners light and evaporator fan is
energized. Check heating effect, then lower the thermostat
setting below the room temperature and verify that the
burners and evaporator fan turn off.

Compressors are internally spring mounted. Do not loosen
or remove compressor hold down bolts.

Internal Wiring
Check all factory and field electrical connections for
tightness. Tighten as required.

Refrigerant Service Ports
Each unit system has two 1/4” SAE flare (with check
valves) service ports: one on the suction line, and one on
the compressor discharge line. Be sure that caps on the
ports are tight.

Refer to Table 11 for the correct orifice to use at high
altitudes.

Heating
1. Purge gas supply line of air by opening union ahead
of the gas valve. If gas odor is detected, tighten union
and wait 5 minutes before proceeding.
2. Turn on electrical supply and manual gas valve.
3. Set system switch selector at HEAT position and fan
switch at AUTO. or ON position. Set heating
temperature lever above room temperature.
4. The induced-- draft motor will start.
5. After a call for heating, the main burners should light
within 5 seconds. If the burner does not light, then
there is a 22-- second delay before another 5-- second
try. If the burner still does not light, the time delay is
repeated. If the burner does not light within 15
minutes, there is a lockout. To reset the control, break
the 24 v power to W1.
6. The evaporator-- fan motor will turn on 45 seconds
after burner ignition.
7. The evaporator-- fan motor will turn off in 45 seconds
after the thermostat temperature is satisfied.
8. Adjust airflow to obtain a temperature rise within the
range specified on the unit nameplate.

Compressor Rotation
On 3-- phase units with scroll compressors, it is important
to be certain compressor is rotating in the proper
direction. To determine whether or not compressor is
rotating in the proper direction:
1. Connect service gauges to suction and discharge
pressure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start-- up.
If the suction pressure does not drop and the discharge
pressure does not rise to normal levels:
4. Note that the evaporator fan is probably also rotating
in the wrong direction.
5. Turn off power to the unit and install lockout tag.
6. Reverse any two of the unit power leads.
7. Re-- energize to the compressor. Check pressures.
The suction and discharge pressure levels should now
move to their normal start-- up levels.
70

NOTE: The default value for the evaporator-- fan motor
on/off delay is 45 seconds. The Integrated Gas Unit
Controller (IGC) modifies this value when abnormal limit
switch cycles occur. Based upon unit operating conditions,
the on delay can be reduced to 0 seconds and the off delay
can be extended to 180 seconds.

The evaporator-- fan off delay can also be modified. Once
the call for heating has ended, there is a 10-- minute period
during which the modification can occur. If the limit
switch trips during this period, the evaporator-- fan off
delay will increase by 15 seconds. A maximum of 9 trips
can occur, extending the evaporator-fan off delay to 180
seconds.
To restore the original default value, reset the power to the
unit.
To shut off unit, set system selector switch at OFF
position. Resetting heating selector lever below room
temperature will temporarily shut unit off until space
temperature falls below thermostat setting.

Ventilation (Continuous Fan)
Set fan and system selector switches at ON and OFF
positions, respectively. Evaporator fan operates
continuously to provide constant air circulation. When the
evaporator-fan selector switch is turned to the OFF
position, there is a 30-- second delay before the fan turns
off.

START--UP, PREMIERLINKt CONTROLS
Use the Carrier network communication software to start
up and configure the PremierLink controller.
Changes can be made using the ComfortWORKSr
software, ComfortVIEWt software, Network Service
Tool, System Pilott device, or Touch Pilott device. The
System Pilot and Touch Pilot are portable interface
devices that allow the user to change system set-- up and
setpoints from a zone sensor or terminal control module.
During start-- up, the Carrier software can also be used to
verify communication with PremierLink controller.
NOTE: All set-- up and setpoint configurations are factory
set and field-- adjustable.
For specific operating instructions, refer to the literature
provided with user interface software.

Perform System Check--Out
1. Check correctness and tightness of all power and
communication connections.

Initial Operation and Test
Perform the following procedure:
1. Apply 24 vac power to the control.
2. Connect the service tool to the phone jack service
port of the controller.
3. Using the Service Tool, upload the controller from
address 0, 31 at 9600 baud rate. The address may be
set at this time. Make sure that Service Tool is
connected to only one unit when changing the
address.
Memory Reset
DIP switch 4 causes an E-- squared memory reset to
factory defaults after the switch has been moved from
position 0 to position 1 and the power has been restored.
To enable the feature again, the switch must be put back
to the 0 position and power must be restored; this prevents
subsequent resets to factory defaults if the switch is left at
position 1.
To cause a reset of the non-- volatile memory (to factory
defaults), turn the controller power off if it is on, move the
switch from position 1 to position 0, and then apply power
to the controller for a minimum of 5 seconds. At this
point, no action occurs, but the controller is now ready for
the memory to reset. Remove power to the controller
again and move the switch from position 0 to position 1.
This time, when power is applied, the memory will reset
to factory defaults. The controller address will return to
bus 0 element 31, indicating that memory reset occurred.
Refer to Rooftop PremierLink Installation, Start-Up, and
Configuration Instructions (Form 33CS-- 58SI) for full
discussion on configuring the PremierLink control system.

START--UP, RTU--MP CONTROL
Field Service Test, explained below, will assist in proper
start-- up. Configuration of unit parameters, scheduling
options, and operation are also discussed in this section.

Field Service Test
The Field Service Test function can be used to verify
proper operation of compressors, heating stages, indoor
fan,
power
exhaust
fans,
economizer,
and
dehumidification. Use of Field Service Test is
recommended at initial system start up and during
troubleshooting. See RTU-- MP Controls, Start-- Up,
Operation, and Troubleshooting Instructions (Form
48-- 50H-- T-- 2T), Appendix A for Field Service Test Mode
table.
71

48TC

If the limit switch trips at the start of the heating cycle
during the evaporator on delay, the time period of the on
delay for the next cycle will be 5 seconds less than the
time at which the switch tripped. (Example: If the limit
switch trips at 30 seconds, the evaporator-- fan on delay for
the next cycle will occur at 25 seconds.) To prevent
short-- cycling, a 5-- second reduction will only occur if a
minimum of 10 minutes has elapsed since the last call for
heating.

2. At the unit, check fan and system controls for proper
operation.
3. At the unit, check electrical system and connections
of any optional electric reheat coil.
4. Check to be sure the area around the unit is clear of
construction dirt and debris.
5. Check that final filters are installed in the unit. Dust
and debris can adversely affect system operation.
6. Verify that the PremierLink controls are properly
connected to the CCN bus.

48TC

Field Service Test mode has the following changes from
normal operation:
S Outdoor air temperature limits for cooling circuits,
economizer, and heating are ignored.
S Normal compressor time guards and other staging delays
are ignored.
S The status of Alarms (except Fire and Safety chain) is
ignored but all alerts and alarms are still broadcasted on
the network.
Field Service Test can be turned ON/OFF at the unit
display or from the network. Once turned ON, other
entries may be made with the display or through the
network. To turn Field Service Test on, change the value
of Test Mode to ON, to turn Field Service Test off, change
the value of Test Mode to OFF.
NOTE: Service Test mode is password protected when
accessing from the display. Depending on the unit model,
factory-- installed options, and field-- installed accessories,
some of the Field Service Test functions may not apply.
The independent outputs (IndpOutputs) submenu is used
to change output status for the supply fan, economizer,
and Power Exhaust. These independent outputs can
operate simultaneously with other Field Service Test
modes. All outputs return to normal operation when Field
Service Test is turned off.
The Cooling submenu is used to change output status for
the individual compressors and the dehumidification relay.
Compressor starts are not staggered. The fans and heating
service test outputs are reset to OFF for the cooling
service test. Indoor fans and outdoor fans are controlled
normally to maintain proper unit operation. All normal
cooling alarms and alerts are functional.
NOTE: Circuit A is always operated with Circuit B due
to outdoor fan control on Circuit A. Always test Circuit A
first, and leave it on to test other Circuits.
The Heating submenu is used to change output status for
the individual heat stages, gas or electric. The fans and
cooling service test outputs are reset to OFF for the
heating service test. All normal heating alarms and alerts
are functional.

Configuration
The RTU-- MP controller configuration points affect the
unit operation and/or control. Review and understand the
meaning and purpose of each configuration point before
changing it from the factory default value. The submenus
containing configuration points are as follows: Unit,
Cooling, Heating, Inputs, Economizer, IAQ, Clock-- Set,
and User Password (USERPW). Each configuration point
is described below under its according submenu. See
RTU-- MP
Controls,
Start-- Up,
Operation,
and
Troubleshooting Instructions (Form 48-- 50H-- T-- 2T),
Appendix for display tables.
Unit
Start Delay
This refers to the time delay the unit will wait after power
up before it pursues any specific operation.
Factory Default = 5 sec
Range = 0-- 600 sec

Filter Service Hours
This refers to the timer set for the Dirty Filter Alarm.
After the number of runtime hours set on this point is
exceeded the corresponding alarm will be generated, and
must be manually cleared on the alarm reset screen after
the maintenance has been completed. The timer will then
begin counting its runtime again for the next maintenance
interval.
Factory Default = 600 hr
NOTE: Setting this configuration timer to 0, disables the
alarm.
Supply Fan Service Hours
This refers to the timer set for the Supply Fan Runtime
Alarm. After the number of runtime hours set on this point
is exceeded the corresponding alarm will be generated,
and must be manually cleared on the alarm reset screen
after the maintenance has been completed. The timer will
then begin counting its runtime again for the next
maintenance interval.
Factory Default = 0 hr
NOTE: Setting this configuration timer to 0, disables the
alarm.
Compressor1 Service Hours
This refers to the timer set for the Compressor 1 Runtime
Alarm. After the number of runtime hours set on this point
is exceeded the corresponding alarm will be generated,
and must be manually cleared on the alarm reset screen
after the maintenance has been completed. The timer will
then begin counting its runtime again for the next
maintenance interval.
Factory Default = 0 hr
NOTE: Setting this configuration timer to 0, disables the
alarm.
Compressor2 Service Hours
This refers to the timer set for the Compressor 2 Runtime
Alarm. After the number of hours set on this point is
exceeded the corresponding alarm will be generated, and
must be manually cleared on the alarm rest screen after
the maintenance has been completed. The timer will then
begin counting its runtime again for the next maintenance
interval
Factory Default = 0 hr
NOTE: Setting this configuration timer to 0, disables the
alarm.
Cooling
Number of Compressor Stages
This refers to the number of mechanical cooling stages
available on a specific unit. Set this point to “One Stage”
if there is one compressor in the specific unit, set to “Two
Stage” if there are two compressors in the unit, and set to
“None” if economizer cooling ONLY is desired.
Factory Default = One Stage for 1 compressor units
Two Stage for 2 compressor units

72

Heating SAT High Setpt
The supply air temperature must remain below this value
to allow heating. There is 5_F plus and minus deadband to
this point. If the SAT rises above this value during heating
the heat stages will begin to decrease until the SAT has
dropped below this value.
Factory Default = 120_F
Range = 95-- 150_F
Heating Lockout Temp
This defines the maximum outdoor air temperature that
heating mode can be enabled and run. If the OAT rises
above this threshold during heating, then heating will not
be allowed.
Factory Default = 65_F
Range = 49-- 95_F
Inputs
NOTE: For installation of inputs and field installed
accessories, refer to the appropriate sections.
Input 3
This input is a discrete input and can be configured to be
one of five different inputs: No Function, Compressor
Safety, Fan Status, Filter Status, or Remote Occupancy.
This input can also be configured to be either Normally
Open (N/O) or Normally Closed (N/C). Input 3 is factory
wired to pin J1-- 2. Field accessories get wired to its
parallel pin J5-- 5. Do not connect inputs to both locations,
one function per input.
Factory Default = Compressor Safety and N/O
NOTE: Compressor Safety input comes from the CLO
board. J1-- 2 is always factory wired to TB1-- 8 (X) terminal
on the unit. If the unit has a CLO board, do not configure
input 3 for anything but Compressor Safety.

Input 5
This input is a discrete input and can be configured to be
one of five different inputs: No Function, Fire Shutdown,
Fan Status, Filter Status, or Remote Occupancy. This
input can also be configured to be either Normally Open
(N/O) or Normally Closed (N/C). Input 5 is factory wired
to pin J1-- 10. Field accessories get wired to its parallel pin
J5-- 3. Do not connect inputs to both locations, one
function per input.
Factory Default = Fire Shutdown and N/C
NOTE: Fire Shutdown input comes from TB4-- 7. J1-- 10
is always factory wired to TB4-- 7. Only change input 5s
function if absolutely needed.
Input 8
This input is a discrete input and can be configured to be
one of five different inputs: No Function, Enthalpy
Switch, Fan Status, Filter Status, or Remote Occupancy.
This input can also be configured to be either Normally
Open (N/O) or Normally Closed (N/C). Input 8 is factory
wired to pin J2-- 6. Field accessories get wired to its
parallel pin J5-- 1. Do not connect inputs to both locations,
one function per input.
Factory Default = No Function and N/O
Input 9
This input is a discrete input and can be configured to be
one of five different inputs: No Function, Humidistat, Fan
Status, Filter Status, or Remote Occupancy. This input can
also be configured to be either Normally Open (N/O) or
Normally Closed (N/C). Input 9 is factory and field wired
to pin J5-- 7. Do not connect inputs to both locations, one
function per input.
Factory Default = Humidistat and N/O
Space Sensor Type
This tells the controller what type of space sensor is
installed to run the unit. The three types that can be used
are the T55 space sensor, the T56 space sensor, or the RS
space sensor.
Factory Default = T55 Type
Input 1 Function
This input is an analog input and can be configured to be
one of five different inputs: No Sensor, IAQ Sensor, OAQ
Sensor, Space RH Sensor, or Outdoor RH Sensor. Input 1
is wired to pin J4-- 5.
Factory Default = No Sensor
Input 2 Function
This input is an analog input and can be configured to be
one of five different inputs: No Sensor, IAQ Sensor, OAQ
Sensor, Space RH Sensor, or Outdoor RH Sensor. Input 2
is wired to pin J4-- 2.
Factory Default = No Sensor
Setpoint Slider Range
This sets the slider range of the space sensor (with this
built in function). The slider is used to offset the current
control setpoint.
Factory Default = 5 n_F
Range = 0-- 15 n_F
73

48TC

Cooling/Econ SAT Low Setpt
The supply air temperature must remain above this value
to allow cooling with the economizer and/or compressors.
There is 5_F plus and minus deadband to this point. If the
SAT falls below this value during cooling, all compressors
will be staged off. The economizer will start to ramp
down to minimum position when the SAT = this
configuration +5_F.
Factory Default = 50_F
Range = 45-- 75_F
Cooling Lockout Temp
This defines the minimum outdoor air temperature that
cooling mode can be enabled and run. If the OAT falls
below this threshold during cooling, then compressor
cooling will not be allowed.
Factory Default = 45_F
Range = 0-- 65_F
Heating

48TC

T55/56 Override Duration
This sets the occupancy override duration when the
override button is pushed on the space sensor.
Factory Default = 1 hr
Range = 0-- 24 hr
IAQ Low Reference @ 4mA
This is used when an IAQ sensor is installed on Input 1 or
2. This value is displayed and used when 4mA is seen at
the input.
Factory Default = 0 PPM
Range = 0-- 400 PPM
IAQ High Reference @ 20mA
This is used when an IAQ sensor is installed on Input 1 or
2. This value is displayed and used when 20mA is seen at
the input.
Factory Default = 2000 PPM
Range = 0-- 5000 PPM
NOTE: IAQ low Reference @ 4mA and IAQ High
Reference @ 20mA are used to set the linear curve of mA
vs. PPM.
OAQ Low Reference @ 4mA
This is used when an OAQ sensor is installed on Input 1
or 2. This value is displayed and used when 4mA is seen
at the input.
Factory Default = 0 PPM
Range = 0-- 400 PPM
OAQ High Reference @ 20mA
This is used when an OAQ sensor is installed on Input 1
or 2. This value is displayed and used when 20mA is seen
at the input.
Factory Default = 2000 PPM
Range = 0-- 5000 PPM
NOTE: OAQ low Reference @ 4mA and OAQ High
Reference @ 20mA are used to set the linear curve of mA
vs. PPM.
Economizer
Economizer Exists
This point tells the controller if there is an economizer
installed on the unit.
Factory Default = NO if no economizer
YES if there is an economizer installed
Economizer Minimum Position
This defines the lowest economizer position when the
indoor fan is running and the building is occupied.
Factory Default = 20%
Range = 0-- 100 %
Economizer High OAT Lockout
If the outdoor air temperature rises above this value,
economizer cooling will be disabled and dampers will
return and stay at minimum position.
Factory Default = 75_F
Range = 55-- 80_F

Power Exhaust Setpt
When the economizer damper position opens above this
point the power exhaust operation will begin. When the
damper position falls 10% below the setpoint, the power
exhaust will shutdown.
Factory Default = 50%
Range = 20-- 90 %
NOTE: This point is only used when Continuous Occ
Exhaust = NO
Continuous Occ Exhaust
This point tells the controller when to run the power
exhaust if equipped on the unit. If set to YES, the power
exhaust will be on all the time when in occupied mode
and will be off when in unoccupied mode. If set to NO the
power exhaust will be controlled by the Power Exhaust
Setpoint.
Factory Default = NO
IAQ
Max Differential CO2 Setpt
If the difference between indoor an outdoor air quality
becomes greater then this value the damper position will
stay at the IAQ Greatest Min Dmpr Pos. configuration
point
Factory Default = 650 PPM
Range = 300-- 950 PPM
IAQ Greatest Min Dmpr Pos.
This is the greatest minimum position the economizer will
open to while trying to control the indoor air quality, CO2
differential.
Factory Default = 50% open
Range = 10-- 60% open
Clockset
This submenu screen allows you to set the date and time
manually. The Daylight Savings Time (DST) can also be
changed here. The date and time is automatically set when
ever software is downloaded. The clock is a 24 hour clock
and not am/pm. The time should be verified (and maybe
changed) according to unit location and time zone.
Factory Default = Eastern Standard Time
USERPW
This submenu screen allows you to change the user
password to a four number password of choice. The User
password change screen is only accessible with the
Administrator Password (1111). The ADMIN password
will always override the user password.

74

Base Unit Controls
Cooling, Units Without Economizer
When thermostat calls for Stage 1 cooling, terminals G
and Y1 are energized. The indoor-- fan contactor (IFC),
outdoor fan contactor (OFC) and Compressor 1 contactor
(C1) are energized and indoor-fan motor, outdoor fan and
Compressor 1 start. The outdoor fan motor runs
continuously while unit is in Stage 1 or Stage 2 cooling.
(D08 and D12 units have two outdoor fans; both run while
unit is in Stage 1 or Stage 2 cooling.)
If Stage 1 cooling does not satisfy the space load , the
space temperature will rise until thermostat calls for Stage
2 cooling (Y2 closes). Compressor 2 contactor (C2) is
energized; Compressor 2 starts and runs.

Heating, Units Without Economizer
When the thermostat calls for heating, terminal W1 is
energized. To prevent thermostat short-cycling, the unit is
locked into the Heating mode for at least 1 minute when
W1 is energized. The induced-draft motor is energized
and the burner ignition sequence begins. The indoor
(evaporator) fan motor (IFM) is energized 45 seconds
after a flame is ignited.
If Stage 1 heating does not satisfy the space load, the
space temperature will fall until thermostat calls for Stage
2 heating (W2 closes). Terminal W2 is energized and the
high-fire solenoid on the main gas valve (MGV) is
energized. Firing rate increases to high-fire. When space
load is partially satisfied, terminal W2 is deenergized; the
high-fire solenoid is deenergized and heating operation
continues on low-- fire.
When the space heating load is fully satisfied, thermostat
terminal W1 is also deenergized. All heating operations
cease. The IFM stops after a 45-second time off delay.

Cooling, Unit With EconoMi$er IV
For Occupied mode operation of EconoMi$er IV, there
must be a 24-v signal at terminals TR and N (provided
through PL6-3 from the unit’s IFC coil). Removing the
signal at N places the EconoMi$er IV control in
Unoccupied mode.
During Occupied mode operation, indoor fan operation
will be accompanied by economizer dampers moving to
Minimum Position setpoint for ventilation. If indoor fan is
off, dampers will close. During Unoccupied mode
operation, dampers will remain closed unless a Cooling
(by free cooling) or DCV demand is received.
When free cooling using outside air is not available, the
unit cooling sequence will be controlled directly by the
space thermostat as described above as Cooling, Unit
Without Economizer. Outside air damper position will be
closed or Minimum Position as determined by occupancy
mode and fan signal.

When free cooling is available as determined by the
appropriate changeover command (dry bulb, outdoor
enthalpy, differential dry bulb or differential enthalpy), a
call for cooling (Y1 closes at the thermostat) will cause
the economizer control to modulate the dampers open and
closed to maintain the unit supply air temperature at 50 to
55_F. Compressor will not run.
During free cooling operation, a supply air temperature
(SAT) above 50_F will cause the dampers to modulate
between Minimum Position setpoint and 100% open. With
SAT from 50_F to 45_F, the dampers will maintain at the
Minimum Position setting. With SAT below 45_F, the
outside air dampers will be closed. When SAT rises to
48_F, the dampers will re-open to Minimum Position
setting.
Should 100% outside air not be capable of satisfying the
space temperature, space temperature will rise until Y2 is
closed. The economizer control will call for compressor
operation. Dampers will modulate to maintain SAT at 50
to 55_F concurrent with Compressor 1 operation. The
Low Ambient Lockout Thermostat will block compressor
operation with economizer operation below 42_F outside
air temperature.
When space temperature demand is satisfied (thermostat
Y1 opens), the dampers will return to Minimum Damper
position if indoor fan is running or fully closed if fan is
off.
If accessory power exhaust is installed, the power exhaust
fan motors will be energized by the economizer control as
the dampers open above the PE-On setpoint and will be
de-- - energized as the dampers close below the PE-On
setpoint.
Damper movement from full closed to full open (or vice
versa) will take between 1-1/2 and 2-1/2 minutes.

Heating With EconoMi$er IV
During Occupied mode operation, indoor fan operation
will be accompanied by economizer dampers moving to
Minimum Position setpoint for ventilation. If indoor fan is
off, dampers will close. During Unoccupied mode
operation, dampers will remain closed unless a DCV
demand is received.
When the room temperature calls for heat (W1 closes), the
heating controls are energized as described in Heating,
Unit Without Economizer above.

Demand Controlled Ventilation
If a field-installed CO2 sensor is connected to the
Economize IV control, a Demand Controlled Ventilation
strategy will operate automatically. As the CO2 level in
the space increases above the setpoint (on the EconoMi$er
IV controller), the minimum position of the dampers will
be increased proportionally, until the Maximum
Ventilation setting is reached. As the space CO2 level
decreases because of the increase in fresh air, the
outdoor-damper will follow the higher demand condition
from the DCV mode or from the free-cooling mode.

75

48TC

OPERATING SEQUENCES

DCV operation is available in Occupied and Unoccupied
periods with EconoMi$er IV. However, a control
modification will be required on the 48TC unit to
implement the Unoccupied period function.

48TC

Supplemental Controls
Compressor Lockout Relay (CLO) - The CLO is available
as a factory-installed option or as a field-- installed
accessory. Each compressor has a CLO. The CLO
compares the demand for compressor operation (via a
24-v input from Y at CLO terminal 2) to operation of the
compressor (determined via compressor current signal
input at the CLO’s current transformer loop); if the
compressor current signal is lost while the demand input
still exists, the CLO will trip open and prevent the
compressor from restarting until the CLO has been
manually reset. In the lockout condition, 24-v will be
available at terminal X. Reset is accomplished by
removing the input signal at terminal 2; open the
thermostat briefly or cycle the main power to the unit.
Phase Monitor Relay (PMR) - The PMR protects the unit
in the event of a loss of a phase or a reversal of power line
phase in the three-- phase unit power supply. In normal
operation, the relay K1 is energized (contact set closed)
and red LED indicator is on steady. If the PMR detects a
loss of a phase or a phase sequence reversal, the relay K1
is energized, its contact set is opened and unit operation is
stopped; red LED indicator will blink during lockout
condition. Reset of the PMR is automatic when all phases
are restored and phase sequence is correct. If no 24-- v
control power is available to the PMR, the red LED will
be off. Smoke Detectors - Factory-- installed smoke
detectors are discussed in detail starting on page 17.

PremierLinkt Control
THERMOSTAT MODE — If the PremierLink controller
is configured for Thermostat mode (TSTAT), it will
control only to the thermostat inputs on J4. These inputs
can be overridden through CCN communication via the
CV_TSTAT points display table. When in this mode, the
fire safety shutdown (FSD) input cannot be used, so any
fire/life safety shutdown must be physically wired to
disable the 24 vac control circuit to the unit.
Indoor Fan — The indoor fan output will be energized
whenever there is 24 vac present on the G input. The
indoor fan will be turned on without any delay and the
economizer damper will open to its minimum position if
the unit has a damper connected to the controller. This
will also occur if the PremierLink controller has been
configured for electric heat or heat pump operation.

Cooling — For cooling operation, there must be 24 vac
present on G. When G is active, the PremierLink
controller will then determine if outdoor conditions are
suitable for economizer cooling when an economizer
damper is available. A valid OAT, SPT (CCN space
temperature) and SAT (supply air temperature) sensor
MUST be installed for proper economizer operation. It
recommended that an outdoor or differential enthalpy
sensor also be installed. If one is not present, then a
jumper is needed on the ENTH input on J4, which will
indicate that the enthalpy will always be low. Economizer
operation will be based only on outdoor air dry bulb
temperature. The conditions are suitable when: enthalpy is
low, OAT is less than OATL High Lockout for TSTAT,
and OAT is less than OATMAX, the high setpoint for free
cooling. The default for OATL is 65_F. The default for
OATMAX is 75_F.
When all of the above conditions are satisfied and all the
required sensors are installed, the PremierLink controller
will use the economizer for cooling. One of three different
control routines will be used depending on the
temperature of the outside air. The routines use a PID loop
to control the SAT to a supply air setpoint (SASP) based
on the error from setpoint (SASPSAT). The SASP is
determined by the routine.
If an economizer is not available or the conditions are not
met for the following economizer routines below, the
compressors 1 and 2 will be cycled based on Y1 and Y2
inputs respectively.
Any time the compressors are running, the PremierLink
controller will lock out the compressors if the SAT
becomes too low. These user configurable settings are
found in the SERVICE configuration table:
Compressor 1 Lockout at SAT < SATLO1 (50 to 65_F)
(default is 55_F)
Compressor 2 Lockout at SAT < SATLO2 (45 to 55_F)
(default is 50_F)
After a compressor is locked out, it may be started again
after a normal time-- guard period and the supply-- air
temperature has increased at least 8_F above the lockout
setpoint.
Routine No. 1: If the OAT ≤ DXLOCK (OAT DX lockout
temperature) and DX Cooling Lockout is enabled when
Y1 input is energized, the economizer will be modulated
to maintain SAT at the Supply Air Setpoint (SASP) =
SATLO1 + 3_F (Supply Air Low Temp lockout for
compressor 1). When Y2 is energized, the economizer
will be modulated to control to a lower SASP = SATLO2
+ 3_F (Supply Air Low Temp lockout for compressor no.
2). Mechanical cooling is locked out and will not be
energized.

76

When Y2 is energized, the economizer will be modulated
to control to a lower supply air setpoint SASP= SATLO2
+ 3_F If the SAT > SASP + 5_F it will close the
economizer to minimum position for 3 minutes, reset the
integrator for the economizer, then start modulating the
economizer to maintain the SASP after the stage two has
been on for 90 seconds. This provides protection for the
compressor against flooded starts and allow refrigerant
flow to stabilize before modulating the economizer again.
By using return air across the evaporator coil just after the
compressor has started allows for increased refrigerant
flow rates providing better oil return of any oil washed out
during compressor start-- up.
Routine No. 3: If the OAT > 68_F and the enthalpy is low
and the OAT < SPT then the economizer will open to
100% and compressors 1 and 2 will be cycled based on
Y1 and Y2 inputs respectively. If any of these conditions
are not met the economizer will go to minimum position.
If there is no call for heating or cooling, the economizer,
if available, will maintain the SASP at 70_F.
Heating — For gas or electric heat, HS1 and HS2 outputs
will follow W1 and W2 inputs respectively. The fan will
also be turned on if it is configured for electric heat.
Heating may also be energized when an IAQ sensor
installed and has overridden the minimum economizer
damper position. If the OAT < 55_F and an IAQ sensor is
installed and the IAQ minimum position > minimum
damper position causing the SAT to decrease below the
SPT - 10_F, then the heat stages will be cycled to temper
the SAT to maintain a temperature between the SPT and
the SPT + 10_F.
Auxiliary Relay configured for Exhaust Fan — If the
Auxiliary Relay is configured for exhaust fan (AUXOUT
= 1) in the CONFIG configuration table and Continuous
Power Exhaust (MODPE) is enable in the SERVICE
configuration table then the output (HS3) will be
energized whenever the G input is on. If the MODPE is
disabled then output will be energized based on the Power
Exhaust Setpoint (PES) in the SETPOINT table.
Indoor Air Quality — If the optional indoor air quality
(IAQI) sensor is installed, the PremierLink controller will
maintain indoor air quality within the space at the
user-- configured differential setpoint (IAQD) in the
CONFIG configuration table. The setpoint is the
difference between the IAQI and an optional outdoor air
quality sensor (OAQ). If the OAQ is not present then a
fixed value of 400 ppm is used. The actual space IAQ
setpoint (IAQS) is calculated as follows:
IAQS = IAQD + OAQ (OAQ = 400 ppm if not present)

As air quality within the space changes, the minimum
position of the economizer damper will be changed also
thus allowing more or less outdoor air into the space
depending on the relationship of the IAQI to the IAQS.
The IAQ algorithm runs every 30 seconds and calculates
IAQ minimum position value using a PID loop on the
IAQI deviation from the IAQS. The IAQ minimum
position is then compared against the user configured
minimum position (MDP) and the greatest value becomes
the final minimum damper position (IQMP). If the
calculated IAQ Minimum Position is greater than the IAQ
maximum damper position (IAQMAXP) decision in the
SERVICE configuration table, then it will be clamped to
IAQMAXP value.
If IAQ is configured for low priority, the positioning of
the economizer damper can be overridden by comfort
requirements. If the SAT < SASP - 8_F and both stages of
heat are on for more then 4 minutes or the SAT > SASP +
5_F and both stages of cooling on for more then 4 minutes
then the IAQ minimum damper position will become 0
and the IQMP = MDP. IAQ mode will resume when the
SAT > SASP - 8_F in heating or the SAT < SASP + 5_F in
cooling.
If the PremierLink controller is configured for 1 stage of
heat and cool or is only using a single stage thermostat
input, this function will not work as it requires the both
Y1 and Y2 or W1 and W2 inputs to be active. In this
application, it is recommended that the user configure
IAQ priority for high.
If IAQ is configured for high priority and the OAT < 55_F
and the SAT < (SPT - 10_F), the algorithm will enable the
heat stages to maintain the SAT between the SPT and the
SPT + 10_F.
CCN SENSOR MODE — When the PremierLink
controller is configured for CCN control, it will control
the compressor, economizer and heating outputs based its
own space temperature input and setpoints or those
received from Linkage. An optional CO2 IAQ sensor
mounted in the space or received through communications
can also influence the economizer and heating outputs.
The PremierLink controller does not have a hardware
clock so it must have another device on the CCN
communication bus broadcasting time. The controller will
maintain its own time once it has received time as long as
it has power and will send a request for time once a
minute until it receives time when it has lost power and
power is restored. The controller will control to
unoccupied setpoints until it has received a valid time.
The controller must have valid time in order to perform
any broadcast function, follow an occupancy schedule,
perform IAQ pre-- occupancy purge and many other
functions as well. The following sections describe the
operation for the functions of the PremierLink controller.

77

48TC

Routine No. 2: If DXLOCK (or DX Cooling Lockout is
disabled) < OAT ≤ 68_F when Y1 input is energized, the
economizer will be modulated to maintain SAT at SASP =
SATLO1 + 3_F. If the SAT > SASP + 5_F and the
economizer position > 85% then the economizer will
close the to minimum position for three minutes or until
the SAT > 68_F. The economizer integrator will then be
reset and begin modulating to maintain the SASP after
stage one has been energized for 90 seconds.

48TC

Indoor Fan — The indoor fan will be turned on whenever
any one of the following conditions are met:
S If the PremierLink controller is in the occupied mode and
ASHRAE 90.1 Supply Fan is configured for Yes in the
CONFIG table. This will be determined by its own
internal occupancy schedule if it is programmed to
follow its local schedule or broadcast its local schedule as
a global schedule, or following a global schedule
broadcast by another device.
S If PremierLink controller is in the occupied mode and
ASHRAE 90.1 Supply Fan is configured for No and there
is a heat or cool demand (fan auto mode)
S If the PremierLink controller is in the occupied mode and
ASHRAE 90.1 Supply Fan is configured for Yes when
Linkage is active and the Linkage Coordinator device is
sending an occupied mode flag
S When Temperature Compensated Start is active
S When Free Cool is active
S When Pre-- Occupancy Purge is active
S Whenever there is a demand for cooling or heating in the
unoccupied mode
S Whenever the Remote Contact input is configured for
Remote Contact (RC_DC=1 in SERVICE table) and it is
closed or the point is forced Closed via communications
in the STATUS01 points display table (remote contact
closed = occupied, remote contact open = unoccupied)
S Whenever the H3_EX_RV point is configured for
Dehumidification (AUXOUT=5 in CONFIG table) and it
is in the unoccupied mode and the indoor RH exceeds the
unoccupied humidity setpoint
S Whenever the Supply Fan Relay point is forced On in the
STATUS01 points display table
The fan will also continue to run as long as compressors
are on when transitioning from occupied to unoccupied
with the exception of Fire Shutdown mode. If the Fire
Shutdown input point is closed or forced in the
STATUS01 points display table, the fan will be shutdown
immediately regardless of the occupancy state or demand.
The PremierLink controller has an optional Supply Fan
Status input to provide proof of airflow. If this is enabled,
the point will look for a contact closure whenever the
Supply Fan Relay is on. If the input is not enabled, then it
will always be the same state as the Supply Fan Relay.
The cooling, economizer and heating routines will use this
input point for fan status.

Cooling — The compressors are controlled by the Cooling
Control Loop that is used to calculate the desired SAT
needed to satisfy the space. It will compare the SPT to the
Occupied Cool Setpoint (OCSP) + the T56 slider offset
(STO) when occupied and the Unoccupied Cool Setpoint
(UCSP + Unoccupied Cooling Deadband) if unoccupied
to calculate a Cooling Submaster Reference (CCSR) that
is then used by the staging algorithm (Cooling submaster
loop) to calculate the required number of cooling stages.
The economizer, if available, will be used as the first
stage of cooling in addition to the compressors. This loop
runs every minute. The following conditions must be met
in order for this algorithm to run:
S indoor fan has been ON for at least 30 seconds
S heat mode is not active and the time guard between
modes equals zero.
S mode is occupied or the Temperature Compensated Start
or Cool mode is active
S SPT reading is available and > (OCSP + STO)
S If mode is unoccupied and the SPT > (UCSP +
Unoccupied Cooling Deadband). The indoor fan will be
turned on by the staging algorithm.
S OAT > DXLOCK or OAT DX Lockout is disabled
If all of the above conditions are met, the CCSR will be
calculated, otherwise it is set to its maximum value and
DX stages is set to 0. If only the last condition is not true
and an economizer is available, it will be used to cool the
space.
The submaster loop uses the CCSR compared to the actual
SAT to determine the required number of capacity stages
to satisfy the load. There is a programmable minimum
internal time delay of 3 to 5 minutes on and 2 to 5 minutes
off for the compressors to prevent short cycling. There is
also a 3-- minute time delay before bringing on the second
stage compressor. If the PremierLink controller is
configured for Heat Pump and AUXOUT is configured for
Reversing Valve Cool, the H3_EX_RV output will
energize 2 seconds after the first compressor is energized
and stay energized until there is a demand for heat. If
AUXOUT is configured for Reversing Valve Heat, then
the H3_EX_RV contact will be deenergized when there is
a demand for cooling. An internal 5 to 10-- minute
user-- programmable time guard between modes prevents
rapid cycling between modes when used in a single zone
application. The Time Guard is lowered to 3 minutes
when Linkage is active to allow the 3Vt linkage
coordinator to have better control of the PremierLink
controller when used as the air source for the 3V control
system.
Table 30 indicates the number of stages available. The
staging algorithm looks at the number of stages available
based the number of cool stages configured in the
SERVICE configuration table. The algorithm will skip the
economizer if it is not available and turn on a compressor.

78

NUMBER OF
STAGES
Compressor 1
Compressor 2

0
Off
Off

1
(ECONOMIZER*)
Off
Off

2

3

On
Off

On
On

* If conditions are suitable for economizer operation.

Any time the compressors are running, the PremierLink
controller will lockout the compressors if the SAT
becomes too low. These user configurable settings are
found in the SERVICE configuration table:
Compressor 1 Lockout at SAT < SATLO1 (50 to 65_F)
(default is 55_F)
Compressor 2 Lockout at SAT < SATLO2 (45 to 55_F)
(default is 50_F)
After a compressor is locked out, it may be started again
after a normal time-- guard period and the supply air
temperature has increased at least 8_F above the lockout
setpoint.
Dehumidification — The PremierLink controller will
provide occupied and unoccupied dehumidification
control when AUXOUT = 5 in the CONFIG table and is
installed on HVAC units that are equipped with additional
controls and accessories to accomplish this function. This
function also requires a space relative humidity sensor be
installed on the OAQ/IRH input.
When in the occupied mode and the indoor relative
humidity is greater then the Occupied High Humidity
setpoint, then the H3_EX_RV output point will be
energized. When in the unoccupied mode and indoor
relative humidity is greater then the Unoccupied High
Humidity setpoint, then the H3_EX_RV output point and
supply fan output will be energized. There is a fixed 5%
hysteresis that the indoor relative humidity must drop
below the active setpoint to end the dehumidification
mode and deenergize the H3_EX_RV output. If the
PremierLink controller is in the unoccupied mode, then
the fan relay will deenergize if there is no other mode
requiring to the fan to be on. This function will not
energize mechanical cooling as a result of the indoor
relative humidity exceeding either setpoint.
A high humidity alarm will be generated if the indoor
relative humidity exceeds the high humidity setpoint by
the amount configured in the Control Humidity Hysteresis
in the ALARMS table for 20 minutes. The alarm will
return to normal when the indoor relative humidity drops
3% below the active humidity setpoint.

Economizer — The economizer dampers are used to
provide free cooling and indoor air quality if optional CO2
sensor is installed and when the outside conditions are
suitable. Temperature control is accomplished by
controlling the SAT to a certain level determined by the
Economizer PID Loop by calculating a submaster
reference (ECONSR) value. This algorithm will calculate
the submaster reference temperature (ECONSR) based on
OAT and enthalpy conditions and cooling requirements.
The ECONSR value is then passed to the Economizer
Submaster Loop, which will modulate dampers to
maintain SAT at ECONSR level.
The following conditions are required to determine if
economizer cooling is possible:
S
S
S
S
S
S
S
S

Indoor fan has been on for at least 30 seconds
Enthalpy is low
SAT reading is available
OAT reading is available
SPT reading is available
OAT ≤ SPT
OAT < OATMAX (OATMAX default is 75_F)
Economizer position is NOT forced

If any of the above conditions are not met, the ECONSR
will be set to its MAX limit of 120_F and the damper will
go to its configured minimum position. The minimum
damper position can be overridden by the IAQ routine
described later in this section.
The calculation for ECONSR is as follows:
ECONSR = PID function on (setpoint - SPT), where:
setpoint = ((OCSP+STO) + (OHSP+STO))/2 when
NTLO (Unoccupied Free Cool OAT Lockout) < OAT <
68_F
setpoint = (OCSP+STO) - 1 when OAT ≤ NTLO
setpoint = (OHSP+STO) + 1 when OAT ≥ 68_F
The actual damper position (ECONPOS) is the result of
the following calculation. Values represented in the right
side of the equation can be found in the SERVICE
configuration table descriptions in this manual. Note that
that the OAT is taken into consideration to avoid large
changes in damper position when the OAT is cold:
ECONPOS = SubGain x (ECONSR-- SAT) + CTRVAL
where SubGain = (OAT - TEMPBAND) / (ESG + 1)
If the OAT < DXLOCK (DX Cool Lockout setpoint) then
the damper will be modulated to maintain the SAT at the
ECONSR value.

79

48TC

Table 30 – Available Cooling Stages

48TC

If the OAT is between DXLOCK and 68_F (DXLOCK <
OAT < 68_F) and additional cooling is required, the
economizer will close the to minimum position for three
minutes, the economizer integrator will then be reset to 0
and begin modulating to maintain the SASP after the stage
has been energized for about 90 seconds. This will allow
the economizer to calculate a new ECONSR that takes
into account the cooling effect that has just been turned on
and not return to the value require before the cooling was
added. This will prevent the economizer from causing
premature off cycles of compressors while maintaining the
low SAT temperature setpoint for the number of stages
active. In addition to preventing compressor short cycling,
by using return air across the evaporator coil just after the
compressor has started allows for increased refrigerant
flow rates providing for better oil return of any oil washed
out during compressor start-- up.

The Staged Heat Submaster Reference (SHSR) is
calculated as follows:
SHSR = Heating PID function on (error) where error =
(OHSP + STO) - Space Temperature
The Maximum SHSR is determined by the SATHI
configuration. If the supply-- air temperature exceeds the
SATHI configuration value, then the heat stages will turn
off. Heat staging will resume after a delay to allow the
supply-- air temperature to drop below the SATHI value.
The maximum number of stages available is dependent on
the type of heat and the number of stages programmed in
the CONFIG and SERVICE configuration tables. Staging
will occur as follows for gas electric units, Carrier heat
pumps with a defrost board, or cooling units with electric
heat:
For Heating PID STAGES = 2
HEAT STAGES = 1 (50% capacity) - energize HS1.
HEAT STAGES = 2 (100% capacity) - energize HS2.
For Heating PID STAGES = 3 and AUXOUT = HS3
HEAT STAGES = 1 (33% capacity if) - energize HS1
HEAT STAGES = 2 (66% capacity) - energize HS2
HEAT STAGES = 3 (100% capacity) - energize HS3

If the OAT > 68_F and OAT < SPT and the number of DX
stages requested is > 0 by the staging algorithm, then
ECONSR is set to its minimum value 48_F and the
damper will go to 100% open.
If the Auxiliary Relay is configured for exhaust fan
(AUXOUT = 1) in the CONFIG configuration table and
Continuous Power Exhaust (MODPE) is Enable in the
SERVICE configuration table, then the AUXO output
(HS3) will be energized whenever the PremierLink
controller is in the occupied mode. If the MODPE is
disabled then AUXO output will be energized based on
the Power Exhaust Setpoint (PES) in the SETPOINT
table.
Heating — The heat stages are controlled by the Heating
Control Loop, which is used to calculate the desired SAT
needed to satisfy the space. It will compare the SPT to the
Occupied Heat Setpoint (OHSP) + the T56 slider offset
(STO) when occupied and the Unoccupied Heat Setpoint
(UHSP - Unoccupied Heating Deadband) if unoccupied to
calculate a Staged Heat Submaster Reference (SHSR).
The heat staging algorithm compares the SHSR to the
actual SAT to calculate the required number of heating
stages to satisfy the load. This loop runs every 40 seconds.
The following conditions must be met in order for this
algorithm to run:
S Indoor fan has been ON for at least 30 seconds.
S Cool mode is not active and the time guard between
modes equals zero.
S Mode is occupied or the Temperature Compensated Start
or Heat mode is active.
S SPT reading is available and < (OHSP + STO).
S If it is unoccupied and the SPT < (UHSP - Unoccupied
Heating Deadband). The indoor fan will be turn on by the
staging algorithm.
When all of the above conditions are met, the SHSR is
calculated and up to 3 stages of heat will turned on and off
to satisfy to maintain the SAT = SHSR. If any of the
above conditions are not met, the SHSR is set to its
minimum value of 35_F.

Staging will occur as follows For heat pump units with
AUXOUT configured as reversing valve:
For Heating PID STAGES = 2 and AUXOUT = Reversing
Valve Heat (the H3_EX_RV output will stay energized
until there is a cool demand) HEAT STAGES = 1 (50%
capacity) shall energize CMP1, CMP2, RVS.
HEAT STAGES = 2 (100% capacity) shall energize HS1
and HS2.
Heating PID STAGES = 3 and AUXOUT = Reversing
Valve Heat (the H3_EX_RV output will stay energized
until there is a cool demand)
HEAT STAGES = 1 (33% capacity if) shall energize
CMP1, CMP2, RVS
HEAT STAGES = 2 (66% capacity) shall energize HS1
HEAT STAGES = 3 (100% capacity) shall energize HS2
If AUXOUT is configured for Reversing Valve Cool, then
the H3_EX_RV contact will be deenergized when there is
a demand for heating. The heat stages will be cycled to
temper the SAT so that it will be between the SPT and the
SPT + 10_F (SPT < SAT < (SPT + 10_F)) if:
the number of heat stages calculated is zero
the OAT < 55_F
an IAQ sensor is installed
the IAQ Minimum Damper Position > minimum damper
position
S and the SAT < SPT - 10_F.
S
S
S
S

80

Indoor Air Quality — If the optional indoor air quality
(IAQI) sensor is installed, the PremierLink controller will
maintain indoor air quality within the space at the user
configured differential setpoint (IAQD) in the CONFIG
configuration table. The setpoint is the difference between
the IAQI and an optional outdoor air quality sensor
(OAQ). If the OAQ is not present then a fixed value of
400 ppm is used. The actual space IAQ setpoint (IAQS) is
calculated as follows:
IAQS = IAQD + OAQ (OAQ = 400 ppm if not present)
As air quality within the space changes, the minimum
position of the economizer damper will be changed also
thus allowing more or less outdoor air into the space
depending on the relationship of the IAQI to the IAQS.
The IAQ algorithm runs every 30 seconds and calculates
IAQ minimum position value using a PID loop on the
IAQI deviation from the IAQS. The IAQ minimum
position is then compared against the user configured
minimum position (MDP) and the greatest value becomes
the final minimum damper position (IQMP). If the
calculated IAQ minimum position is greater than the IAQ
maximum damper position (IAQMAXP) decision in the
SERVICE configuration table, then it will be clamped to
IAQMAXP value.
If IAQ is configured for low priority, the positioning of
the economizer damper can be overridden by comfort
requirements. If the SPT > OCSP + 2.5 or the SPT <
OHSP - 2.5 then IAQ minimum position becomes 0 and
the IQMP = MDP. The IAQ mode will resume when the
SPT ≤ OCSP + 1.0 and SPT ≥ OHSP - 1.0.
If IAQ is configured for high priority and the OAT < 55_F
and the SAT < (SPT - 10_F), the algorithm will enable the
heat stages to maintain the SAT between the SPT and the
SPT + 10_F.
IAQ Pre-- Occupancy Purge — This function is designed to
purge the space of airborne contaminants that may have
accumulated 2 hours prior to the beginning of the next
occupied period. The maximum damper position that will
be used is temperature compensated for cold whether
conditions and can be pre-- empted by Temperature
Compensated Start function. For pre-- occupancy to occur,
the following conditions must be met:
S IAQ Pre-- Occupancy Purge option is enabled in the
CONFIG configuration table
S Unit is in the unoccupied state
S Current Time is valid
S Next Occupied Time is valid
S Time is within 2 hours of next Occupied period
S Time is within Purge Duration (user-- defined 5 to 60
minutes in the CONFIG configuration table)

S OAT Reading is available
If all of the above conditions are met, the economizer
damper IQMP is temporarily overridden by the
pre-- occupancy damper position (PURGEMP). The
PURGEMP will be set to one of the following conditions
based on atmospheric conditions and the space
temperature:
S If the OAT ≥ NTLO (Unoccupied OAT Lockout
Temperature) and OAT < 65_F and OAT is less than or
equal to OCSP and Enthalpy = Low then PURGEMP =
100%.
S If the OAT < NTLO then PURGEMP = LTMP (Low
Temperature Minimum Position - defaults to 10%)
S If the OAT > 65_F or (OAT ≥ NTLO and OAT > OCSP)
or Enthalpy = High then PURGEMP = HTMP (High
Temperature Minimum Position defaults to 35%).
The LTMP and HTMP are user adjustable values from 0
to 100% in the SETPOINT table. Whenever PURGEMP
results in a number greater than 0%, the IAQ
pre-- occupancy purge mode will be enabled turning on the
Indoor Fan Relay and setting the economizer IQMP to the
PURGEMP value. When IAQ pre-- occupancy mode is not
active PURGEMP = 0%.
Unoccupied Free Cooling — Unoccupied free cool
function will start the indoor fan during unoccupied times
in order to cool the space with outside air. This function is
performed to delay the need for mechanical cooling when
the system enters the occupied period. Depending on how
Unoccupied Free Cooling is configured, unoccupied mode
can occur at any time in the unoccupied time period or 2
to 6 hours prior to the next occupied time. Once the space
has been sufficiently cooled during this cycle, the fan will
be stopped. In order to perform unoccupied free cooling
all of the following conditions must be met:
S NTEN option is enabled in the CONFIG configuration
table
S Unit is in unoccupied state
S Current time of day is valid
S Temperature Compensated Start mode is not active
S COOL mode is not active
S HEAT mode is not active
S SPT reading is available
S OAT reading is available
S Enthalpy is low
S OAT > NTLO (with 1_F hysteresis) and < Max Free Cool
setpoint
If any of the above conditions are not met, Unoccupied
Free Cool mode will be stopped, otherwise, the mode will
be controlled as follows:
The NTFC setpoint (NTSP) is determined as NTSP =
(OCSP + OHSP) / 2
The Unoccupied Free Cool mode will be started when:
SPT > (NTSP + 2_F) and SPT > (OAT + 8_F)
The Unoccupied Free Cool mode will be stopped when:
SPT < NTSP or SPT < (OAT + 3_F)
81

48TC

There is also a SAT tempering routine that will act as SAT
low limit safety to prevent the SAT from becoming too
cold should the economizer fail to close. One stage of
heating will be energized if it is not in the Cooling or Free
Cooling mode and the OAT is below 55_F and the SAT is
below 40_F. It will deenergize when the SAT > (SPT +
10_F).

Temperature Compensated Start — This function will run
when the controller is in unoccupied state and will
calculate early start bias time (SBT) based on space
temperature deviation from occupied setpoints in minutes
per degree. The following conditions will be met for the
function to run:
Unit is in unoccupied state
Next occupied time is valid
Current time of day is valid
Valid space temperature reading is available (from sensor
or linkage thermostat)
S Cool Start Bias (KCOOL) and Heat Bias Start (KHEAT)
> 0 in the CONFIG configuration table
48TC

S
S
S
S

The SBT is calculated by one of the following formulas
depending on temperature demand:
If SPT > OCSP then SBT = (SPT - OCSP) * KCOOL
If SPT < OHSP then SPT = (OHSP - SPT) * KHEAT.
The calculated start bias time can range from 0 to 255
minutes. When SBT is greater than 0 the function will
subtract the SBT from the next occupied time to calculate
a new start time. When a new start time is reached, the
Temperature Compensated Start mode is started. This
mode energizes the fan and the unit will operate as though
it is in occupied state. Once set, Temperature
Compensated Start mode will stay on until the unit returns
to occupied state. If either Unoccupied Free Cool or IAQ
Pre-- Occupancy mode is active when Temperature
Compensated Start begins, their mode will end.
Door Switch — The Door Switch function is designed to
disable mechanical heating and cooling outputs when the
REMOCC contact input is closed (in the ON state) after a
programmed time delay. The fan will continue to operate
based on the current mode and the ASHRAE 90.1 Supply
Fan setting. The delay is programmable from 2 to 20
minutes by setting the Remote Cont/Door Switch decision
in the SERVICE table to a value equal to the number of
minutes desired. When the contact is open (in the OFF
state), the PremierLink controller will resume normal
temperature control.
This application is designed for use in schools or other
public places where a door switch can be installed to
monitor the opening of a door for an extended period of
time. The controller will disable mechanical cooling and
heating when the door is open for a programmed amount
of time.

This function can also be used to monitor a high
condensate level switch when installed on a water source
heat pump to disable mechanic cooling in case of a
plugged evaporator condensate pan drain.
Linkage — The Linkage function in the PremierLink
controller is available for applications using a Linkage
thermostat or the 3V control system. If using the Linkage
thermostat, both the PremierLink controller and the stat
must be on the same CCN bus. When used as the air
source for a 3V control system, the PremierLink controller
is not required to be on the same CCN bus but it is
recommended. Linkage will be active when it is initiated
from the Linkage thermostat or the 3V Linkage
Coordinator through CCN communications and requires
no configuration. Only one device can be linked to the
PremierLink controller.
Once Linkage is active, the PremierLink controller’s own
SPT, temperature setpoints, and occupancy are ignored
and the controller will use the information provided by the
remote linkage device. The following information will be
received from the remote linked device and can be viewed
in the maintenance display table:
S
S
S
S
S
S
S
S
S
S

Supervisory Element
Supervisory Bus
Supervisory Block
Average Occupied Heat Setpoint
Average Occupied Cool Setpoint
Average Unoccupied Heat Setpoint
Average Unoccupied Cool Setpoint
Average Zone Temp
Average Occupied Zone Temp
Occupancy Status

In return, the PremierLink controller will provide its SAT
and operating mode to the linked device.
It will convert its operating modes to Linkage modes. See
Table 31.
Table 31 – Linkage Modes
ROOFTOP MODE
Demand Limit
Heat
Cool or Free Cooling
IAQ Control
Temp. Compensated
Start Heat
Temp. Compensated
Start Cool
IAQ Purge
Occupied
(Indoor Fan ON)
Unoccupied Free
Cool
Fire Shutdown
Factory/Field Test
Off

82

VALUE
N/A
3
4
N/A

LINKAGE MODE
N/A
Heating
Cooling
N/A

2

Warm ---up

4

Cooling

6

Pressurization

4

Cooling

5
7
1
1

Unoccupied Free
Cooling
Evac
Off
Off

For more information on how the PremierLink controller
is used in conjunction with the Carrier 3V control system,
contact your CCN controls representative.
IMPORTANT: The PremierLink controller should not be
used as a linked air source in a ComfortIDt VAV system.
The ComfortID VAV system will NOT function correctly
when applied with a PremierLink controller as the air
source, resulting in poor comfort control and possible
equipment malfunction.
NOTE: The PremierLink controller can be used as an air
source in a 3V Pressure Independent (PI) System (a 3V
Linkage Coordinator with ComfortID PI Zone
Controllers), but it should not be used as an air source
with ComfortID controllers unless a 3V zone controller is
used as the Linkage Coordinator. Contact your Carrier
CCN controls representative for assistance.
Demand Limit — If the demand limit option is enabled,
the control will receive and accept Redline Alert and
Loadshed commands from the CCN loadshed controller.
When a redline alert is received, the control will set the
maximum stage of capacity equal to the stage of capacity
that the unit is operating at when the redline alert was
initiated.
When loadshed command is received the control will
reduce capacity as shown in Table 32.
Table 32 – Loadshed Command — Gas and Electric
Heat Units
CURRENT CAPACITY
CMP1
CMP1+CMP2
HS1
HS1+HS2 (+HS3)

NEW CAPACITY
DX Cooling OFF
CMP1
Heat OFF
HS1

The controller will have a maximum demand limit timer
of 1 hour that prevents the unit from staying in load shed
or redline alert longer than 1 hour in the event the
controller loses communication with the network load
shed module. Should the maximum demand limit timer
expire prior to receiving the loadshed device command
from CCN, the control will stop demand limit mode and
return to normal operation.

RTU--MP Sequence of Operation
The RTU-- MP will control the compressor, economizer
and heating outputs based on its own space temperature
input and setpoints. An optional CO2 IAQ sensor mounted
in the space can influence the economizer minimum
position. The RTU-- MP has its own hardware clock that is
set automatically when the software is installed on the
board. The RTU-- MP’s default is to control to occupied
setpoints all the time, until a type of occupancy control is
set. Occupancy types are described in the scheduling
section. The following sections describe the operation for
the functions of the RTU-- MP. All point objects that are
referred to in this sequence will be in reference to the
objects as viewed in BACview6 Handheld.
Scheduling
Scheduling is used to start heating or cooling (become
occupied) based upon a day of week and a time period and
control to the occupied heating or cooling setpoints.
Scheduling functions are located under occupancy
determination and the schedule menu accessed by the
Menu softkey (see Appendix - for menu structure). Your
local time and date should be set for these functions to
operate properly. Five scheduling functions are available
by changing the Occupancy Source to one of the
following selections:
Always Occupied (Default Occupancy)
The unit will run continuously. RTU-- MP ships from the
factory with this setting.
Local Schedule
The unit will operate according to the schedule configured
and stored in the unit. The local schedule is made up of
three hierarchy levels that consist of two Override
schedules, twelve Holiday and four Daily schedules, and
are only accessible by the BACview screen (handheld or
virtual).
The Daily schedule is the lowest schedule in the hierarchy
and is overridden by both the Holiday and Override
schedule. It consists of a start time, a stop time (both in 24
hour mode) and the seven days of the week, starting with
Monday and ending in Sunday. To select a daily schedule
scroll to the Schedules menu off of the Menu selection.
Enter the User password and change the Occupancy
Source to Local Schedule. Scroll down and over to the
Daily menu and press enter. Choose one of the four Daily
schedules by pressing the Next softkey and change the
Use? point from NO to YES by selecting the point and
pressing the INCR or DECR softkey. Press the OK softkey
and scroll to the start and stop times. Edit these times
following the same steps as the Use? point. Finally scroll
down to the Days: section and highlight the days required
for the Daily schedule by INCR or DECR softkeys and
press OK softkey.

83

48TC

The PremierLinkt controller will generate a Linkage
Communication Failure alarm if a failure occurs for 5
consecutive minutes once a Linkage has previously been
established. It will then revert back to its own SPT,
setpoints and occupancy schedule for control. For this
reason, Carrier strongly recommends that an SPT be
installed in the space on open plenum systems or in the
return air duct of ducted return air systems to provide
continued
backup
operation.
When
Linkage
communication is restored, the controller will generate a
return to normal.

48TC

The Holiday schedule is created to override the Daily
schedule and identify a specific day and month of the year
to start and stop the unit and change control to the
unoccupied heating and cooling setpoints. Follow the
same steps to turn on one of the twelve Holiday schedules
and start and stop times. Next, select one out of the twelve
months and one out of the thirty-- one days of that month.
The RTU-- MP will now ignore the Daily schedule for the
specific day and time you selected and follow the Holiday
Schedule for this period.
The Override schedules primary purpose is to provide a
temporary change in the occupied heating and cooling
setpoints and force the unit to control to the unoccupied
heating and cooling setpoints. This would occur on a set
day in a particular month and last during the start and stop
time configured. The Override schedule is enabled by
following the same steps to create the Holiday schedule.
NOTE: Push button override is only available when
running a local or BACnet Schedule.
BACnet Schedule
For use with a Building Automation System that supports
native BACnet scheduling is scheduling the unit. With the
Occupancy Source set to BACnet schedule the BAS will
control the unit through network communication and it’s
own scheduling function.
BAS On/Off
The Building Automation System is scheduling the unit
via an On/Off command to the BAS ON/OFF software
point. The Building Automation System can be speaking
BACnet, Modbus, or N2 and is writing to the BAS On/Off
point in the open protocol point map.
NOTE:
If the BAS supports NATIVE BACnet
scheduling, then set the Occupancy Source to BACnet
schedule. If the BAS is BACnet but does NOT support
NATIVE BACnet scheduling, then set the Occupancy
Source to BAS On/Off.
DI On/Off
A hard-- wired input on the RTU-- MP will command the
unit to start/stop. Inputs 3, 5, 8, and 9 on plug J5 can be
hard-- wired to command the unit to start/stop.
NOTE: Scheduling can either be controlled via the unit
or the BAS, but NOT both.
Indoor Fan
The indoor fan will be turned on whenever any one of the
following conditions is true:
S It is in the occupied mode. This will be determined by its
own internal occupancy schedule.
S Whenever there is a demand for cooling or heating in the
unoccupied mode.
S Whenever the remote occupancy switch is closed during
DI On/Off schedule type or if occupancy is forced
occupied by the BAS during BAS On/Off schedule type.

When transitioning from unoccupied to occupied, there
will be a configured time delay of 5 to 600 seconds before
starting the fan. The fan will continue to run as long as
compressors, heating stages, or the dehumidification
relays are on when transitioning from occupied to
unoccupied with the exception of Shutdown mode. If Fire
Shutdown, safety chain, SAT alarm or SPT alarm are
active; the fan will be shutdown immediately regardless of
the occupancy state or demand.
The RTU-- MP has an optional Supply Fan Status input to
provide proof of airflow. If this is enabled, the point will
look for a contact closure whenever the Supply Fan Relay
is on. If it is not enabled then it will always be the same
state as the Supply Fan Relay. The cooling, economizer,
heating, dehumidification, CO2 and power exhaust
routines will use this input point for fan status.
Cooling
The compressor outputs are controlled by the Cooling
Control PID Loop and Cooling Stages Capacity algorithm.
They will be used to calculate the desired number of
stages needed to satisfy the space by comparing the Space
Temperature (SPT) to the Occupied Cool Setpoint plus the
T56 slider offset when occupied and the Unoccupied Cool
Setpoint (UCSP) plus the T56 slider offset, if unoccupied.
The economizer, if available, will be used for cooling in
addition to the compressors. The following conditions
must be true in order for this algorithm to run:
S Indoor Fan has been ON for at least 30 seconds.
S Heat mode is not active and the time guard between
modes equals zero.
S If occupied and the SPT >(occupied cool setpoint plus
the T56 slider offset).
S Space Temperature reading is available.
S If it is unoccupied and the SPT > (unoccupied cool
setpoint plus the T56 slider offset). The indoor fan will be
turned on by the staging algorithm.
S If economizer is available and active and economizer
open > 85% and SAT > (SAT low limit + 5_F) and SPT >
effective setpoint + 0.5_F.
OR
Economizer is available, but not active
OR
Economizer is not available
S OAT > DX Lockout temperature.
If all of the above conditions are met, the compressors
will be energized as required, otherwise they will be
de-- energized.
There is a fixed 3-- minute minimum on time and a
5-- minute off time for each compressor output and a
3-- minute minimum time delay between staging up or
down.
Any time the compressors are running the RTU-- MP will
stage down the compressors if the SAT becomes less than
the cooling low supply air setpoint.
After a compressor is staged off, it may be started again
after a normal time-- guard period and the supply air
temperature has increased above the low supply air
setpoint.

84

If RTU-- MP is also controlling an exhaust fan, it can be
enabled based on damper position or by occupancy. If
configured for continuous occupied operation, it will be
energized whenever the controller is in the occupied mode
and disabled when in the unoccupied mode. If configured
for damper position control, it will be energized whenever
the economizer exceeds the power exhaust setpoint and
disabled when the economizer drops below the setpoint by
a fixed hysteresis of 10%.
Heating
The heating outputs are controlled by the Heating Control
PID Loop and Heating Stages Capacity algorithm. They
will be used to calculate the desired number of stages
needed to satisfy the space by comparing the SPT to the
Occupied Heat Setpoint plus the T56 slider offset when
occupied and the Unoccupied Heat Setpoint plus the T56
slider offset if unoccupied. The following conditions must
be true in order for this algorithm to run:
S Indoor Fan has been ON for at least 30 seconds.
S Cool mode is not active and the time guard between
modes equals zero.

S If occupied and SPT <(occupied heat setpoint plus T56
slider offset)
S SPT reading is available
S If it is unoccupied and the SPT < (unoccupied heat
setpoint plus T56 slider offset). The indoor fan will be
turned on by the staging algorithm.
S OAT < High OAT lockout temperature.
If all of the above conditions are met, the heating outputs
will be energized as required, otherwise they will be
de-- energized. If the SAT begins to exceed the high supply
air setpoint, a ramping function will cause the Heat Stages
Capacity algorithm to decrease the number of stages until
the SAT has dropped below the setpoint.
There is a fixed one minute minimum on time and a one
minute off time for each heat output. Heat staging has a 3
minute stage up and 30 second stage down delay.
Indoor Air Quality
If the optional indoor air quality sensor is installed, the
RTU-- MP will maintain indoor air quality within the space
at the user configured differential setpoint. The setpoint is
the difference between the indoor air quality and an
optional outdoor air quality sensor. If the outdoor air
quality is not present then a fixed value of 400ppm is
used. The following conditions must be true in order for
this algorithm to run:
S The mode is occupied.
S Indoor Fan has been ON for at least 30 seconds.
S Indoor Air Quality sensor has a valid reading
As air quality within the space changes, the minimum
position of the economizer damper will be changed thus
allowing more or less outdoor air into the space depending
on the relationship of the indoor air quality to the
differential setpoint. If all the above conditions are true,
the IAQ algorithm will run and calculates an IAQ
minimum position value using a PID loop. The IAQ
minimum damper position is then compared against the
user configured economizer minimum position and the
greatest value becomes the final minimum damper
position of the economizer output.
If the calculated IAQ minimum position is greater than
the IAQ maximum damper position configuration then it
will be clamped to the configured value.
Demand Limit
If the RTU-- MP receives a level 1 (one degree offset), 2
(two degree offset), or a 3 (4 degree offset) to the BACnet
demand limit variable, the controller will expand the
heating and cooling setpoints by the configured demand
limit setpoint value and remain in effect until the BACnet
demand limit variable receives a 0 value.

FASTENER TORQUE VALUES
See Table 33 for torque values.

85

48TC

Economizer
The Economizer dampers are used to provide free cooling
and Indoor Air Quality, if optional CO2 sensor is installed,
when the outside conditions are suitable.
The following conditions must be true for economizer
operation:
S Indoor Fan has been on for at least 30 seconds.
S Enthalpy is Low if the Enthalpy input is enabled.
S SAT reading is available.
S OAT reading is available.
S SPT reading is available.
S OAT <= High OAT economizer lockout configuration
(default = 75).
S OAT <= SPT
If any of the mentioned conditions are not true, the
economizer will be set to its configured minimum
position. The minimum damper position can be
overridden by the IAQ routine described later in this
section.
If the above conditions are true, the Economizer Control
Master Loop will calculate a damper position value based
on the following calculation:
Damper Position = minimum position + PID (SPT - econ
setpoint). Econ setpoint is half way between the effective
cool and heat setpoints. If the SAT drops below the
cooling low supply air setpoint (+ 5_F), the economizer
will ramp down to minimum position.
Power Exhaust

Table 33 – Torque Values
120 ¦ 12 in ---lbs

13.5 ¦ 1.4 Nm

Supply fan motor adjustment plate

120 ¦ 12 in ---lbs

13.5 ¦ 1.4 Nm

Motor pulley setscrew

72 ¦ 5 in ---lbs

8.1 ¦ 0.6 Nm

Fan pulley setscrew

72 ¦ 5 in ---lbs

8.1 ¦ 0.6 Nm

Blower wheel hub setscrew
Bearing locking collar setscrew
Compressor mounting bolts

72 ¦ 5 in ---lbs
65 to70 in ---lbs
65 to75 in ---lbs

8.1 ¦ 0.6 Nm
7.3 to 7.9 Nm
7.3 to 7.9 Nm

Condenser fan motor mounting bolts

20 ¦ 2 in ---lbs

2.3 ¦ 0.2 Nm

Condenser fan hub setscrew

84 ¦ 12 in ---lbs

9.5 ¦ 1.4 Nm

48TC

Supply fan motor mounting

86

APPENDIX I. MODEL NUMBER SIGNIFICANCE
Model Number Nomenclature
2

3

8

4

5

6

7

T C D D 0

____

____

8

9

10 11 12 13 14 15 16 17 18

8 A 1 A 5 -- 0 A 0 A 0

____

Unit Heat Type
48 = Cooling/Gas Heat RTU

Brand / Packaging
0 = Standard
1 = LTL

Tier / Model
TC = Entry tier (with PuronR refrigerant)

Electrical Options
A = None
C = Non--- fused disc
D = Thru the base
F = Non--- fused & thru the base

Heat Size
D = Low heat
E = Medium heat
F = High heat
S = Stainless steel, low heat
R = Stainless steel, medium heat
T = Stainless steel, high heat

Service Options
0 = None
1 = Unpowered convenience outlet
2 = Powered convenience outlet
Intake / Exhaust Options
A = None
B = Temp econo w/ baro relief
F = Enthalpy econo w/ baro relief
K = 2--- Position damper

Refrig. System Options
D = 2--- stg. cooling comp. w/NOVATIONt coil

Base Unit Controls
0 = Electromechanical
1 = PremierLink DDC controller
2 = RTU--- MP multi protocol controller

Cooling Tons
08 = 7.5 Ton
12 = 10 Ton
14 = 12.5 Ton

Design Rev
Factory assigned

Sensor Options
A = None
B = RA smoke detector
C = SA smoke detector
D = RA & SA smoke detector
E = CO2 sensor
F = RA smoke detector & CO2
G = SA smoke detector & CO2
H = RA & SA smoke detector & CO2

Voltage
1 = 575/3/60
5 = 208--- 230/3/60
6 = 460/3/60

2---Stage Cooling Coil Options (Outdoor --- Indoor)
G = Al/Al --- Al/Cu
T = Al/Al --- Al/Cu --- Louvered Hail Guards

Indoor Fan Options
1 = Standard static option
2 = Medium static option
3 = High static option

Serial Number Format
POSITION NUMBER
TYPICAL

1
4
POSITION
1--- 2
3--- 4
5
6--- 10

2
8

3
0

4
8

5
G

6
1

7
2

8
3

DESIGNATES
Week of manufacture (fiscal calendar)
Year of manufacture (“08” = 2008)
Manufacturing location (G = ETP, Texas, USA)
Sequential number

87

9
4

10
5

48TC

1

4

APPENDIX II. PHYSICAL DATA

48TC*D08

48TC*D12

48TC*D14

2 / 2 / Scroll

2 / 2 / Scroll

2 / 2 / Scroll

4--- 6 / 4--- 6

6--- 0 / 6--- 0

7--- 6/8--- 0

42 / 42
Accutrol
630 / 505
54 / 117

42 / 42
Accutrol
630 / 505
54 / 117

56 / 56
Accutrol
630 / 505
54 / 117

Cu / Al
3/8” RTPF
3 / 15
8.9
3/4”

Cu / Al
3/8” RTPF
4 / 15
11.1
3/4”

Cu / Al
3/8” RTPF
4 / 15
11.1
3/4”

Standard Static
3 phase

7.5 -- 12.5TONS

Motor Qty / Drive Type
Max BHP
RPM Range
Motor Frame Size
Fan Qty / Type
Fan Diameter (in)

1 / Belt
1.7
489--- 747
56
1 / Centrifugal
15 x 15

1 / Belt
2.4
591--- 838
56
1 / Centrifugal
15 x 15

1 / Belt
2.9*
652--- 843
56
1 / Centrifugal
15 x 15

Medium Static
3 phase

(Cooling)

Motor Qty / Drive Type
Max BHP
RPM Range
Motor Frame Size
Fan Qty / Type
Fan Diameter (in)

1 / Belt
2.9*
733--- 949
56
1 / Centrifugal
15 x 15

1 / Belt
3.7
838--- 1084
56
1 / Centrifugal
15 x 15

1 / Belt
3.7
838--- 1084
56
1 / Centrifugal
15 x 15

High Static
3 phase

48TC

Physical Data

Motor Qty / Drive Type
Max BHP
RPM Range
Motor Frame Size
Fan Qty / Type
Fan Diameter (in)

1 / Belt
4.7
909--- 1102
145TY
1 / Centrifugal
15 x 15

1 / Belt
4.7
1022--- 1240
145TY
1 / Centrifugal
15 x 15

1 / Belt
4.7
1022--- 1240
145TY
1 / Centrifugal
15 x 15

Al / Al
NOVATION ™
1 / 20
20.5

Al / Al
NOVATION ™
1 / 20
25.1

Al / Al
NOVATION ™
2 / 20
25.1

2/ Direct
1/4 / 1100
22

2 / Direct
1/4 / 1100
22

1/ Direct
1 / 1175
30

4 / 16 x 20 x 2
1 / 20 x 24 x 1

4 / 20 x 20 x 2
1 / 20 x 24 x 1

4 / 20 x 20 x 2
1 / 20 x 24 x 1

Refrigeration System
# Circuits / # Comp. / Type
PuronR refrig. (R--- 410A) charge per
circuit A/B (lbs--- oz)
Oil A/B (oz)
Metering Device
High--- press. Trip / Reset (psig)
Low--- press. Trip / Reset (psig)
Evaporator Coil
Material
Coil type
Rows / FPI
Total Face Area (ft2)
Condensate Drain Conn. Size
Evaporator Fan and Motor

Condenser Coil

Condenser fan / motor

Filters

Material
Coil type
Rows / FPI
Total Face Area (ft2)
Qty / Motor Drive Type
Motor HP / RPM
Fan diameter (in)

RA Filter # / Size (in)
OA inlet screen # / Size (in)

AI / AI: Aluminum Tube / Aluminum Fin
Cu / AI: Copper Tube / Aluminum Fin
RTPF: Round Tube / Plate Fin
* 575V motor utilizes 3.7 BHP

88

APPENDIX II. PHYSICAL DATA (cont.)
Physical Data

(Heating)

7.5 -- 12.5TONS

48TC**08

48TC**12

48TC**14

1
4--- 13 / 0.18--- 0.47
11--- 13 / 0.40--- 0.47

1
4--- 13 / 0.18--- 0.47
11--- 13 / 0.40--- 0.47

1
4--- 13 / 0.18--- 0.47
11--- 13 / 0.40--- 0.47

0.14
0.14

0.14
0.14

0.14
0.14

Natural Gas Heat, Liquid Propane Heat
# of stages / # of burners (total)
Connection size
Rollout switch opens / Closes
Temperature rise (min/max)

1/3
1/2” NPT
195 / 115
20 --- 50

2/4
3/4” NPT
195 / 115
25 --- 65

2/4
3/4” NPT
195 / 115
25 --- 65

# of stages / # of burners (total)
Connection size
Rollout switch opens / Closes
Temperature rise (min/max)

2/4
3/4” NPT
195 / 115
35 --- 65

2/5
3/4” NPT
195 / 115
30 --- 65

2/5
3/4” NPT
195 / 115
25 --- 65

# of stages / # of burners (total)
Connection Size
Rollout switch opens / Closes
Temperature rise (min/max)

2/5
3/4” NPT
195 / 115
45 --- 75

2/5
3/4” NPT
195 / 115
35 --- 70

2/5
3/4” NPT
195 / 115
35 --- 70

Gas Connection
# of Gas Valves
Nat. gas supply line press (in. w.g.)/(PSIG)
LP supply line press (in. w.g.)/(PSIG)

HIGH

MED

LOW

1st stage
2nd stage

89

48TC

Heat Anticipator Setting (Amps)

APPENDIX III. FAN PERFORMANCE
48TC**08
CFM

48TC

2250
2438
2625
2813
3000
3188
3375
3563
3750

CFM
2250
2438
2625
2813
3000
3188
3375
3563
3750

3 PHASE
0.2
RPM

BHP

RPM

505
533
562
591
621
652
682
713
745

0.52
0.62
0.74
0.88
1.03
1.21
1.40
1.61
1.85

586
610
635
661
688
715
743
772
801

1.2
RPM

BHP

838
854
872
890
910
930
951
973
996

1.81
1.96
2.12
2.31
2.51
2.74
2.99
3.26
3.55

7.5 TON HORIZONTAL SUPPLY

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.4
0.6
0.8
BHP
RPM
BHP
RPM
Standard Static Option
0.73
657
0.97
722
0.85
679
1.09
742
0.98
701
1.23
762
1.13
725
1.39
783
1.29
749
1.57
806
1.48
774
1.77
829
1.68
800
1.98
853
1.91
826
2.22
878
2.15
853
2.48
903

BHP
1.22
1.36
1.51
1.68
1.87
2.07
2.30
2.55
2.82

1.0
RPM
BHP
Medium Static Option
782
1.50
800
1.65
819
1.81
839
1.98
859
2.18
881
2.40
903
2.63
927
2.89
951
3.18

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
1.4
1.6
1.8
2.0
RPM
BHP
RPM
BHP
RPM
BHP
RPM
BHP
Medium Static Option
High Static Option
891
2.12
941
2.46
988
2.82
1033
3.19
906
2.28
955
2.63
1001
2.99
1046
3.37
922
2.46
970
2.81
1016
3.17
1060
3.56
940
2.65
986
3.01
1031
3.38
1074
3.77
958
2.86
1004
3.23
1048
3.61
1090
4.01
977
3.10
1022
3.47
1065
3.86
1107
4.261
997
3.35
1041
3.74
1083
4.13
1124
4.54
1018
3.63
1061
4.02
1103
4.43
1040
3.93
1082
4.34
-

NOTE: For more information, see General Fan Performance Notes on page 87.
Boldface indicates field-- supplied drive is required.
1. Recommend using field-- supplied fan pulley (part no. KR11AZ002) and belt (part no. KR29AF054).

48TC**08
CFM
2250
2438
2625
2813
3000
3188
3375
3563
3750

CFM
2250
2438
2625
2813
3000
3188
3375
3563
3750

3 PHASE
0.2
RPM

BHP

RPM

513
541
570
600
629
660
690
721
752

0.54
0.65
0.77
0.91
1.07
1.25
1.45
1.67
1.91

595
620
645
672
699
726
754
783
812

1.2
RPM

BHP

839
858
878
899
920
942
964
988
1011

1.86
2.02
2.20
2.40
2.62
2.86
3.12
3.41
3.71

7.5 TON VERTICAL SUPPLY

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.4
0.6
0.8
BHP
RPM
BHP
RPM
Standard Static Option
0.76
665
1.01
728
0.89
688
1.14
750
1.02
712
1.29
772
1.18
736
1.46
794
1.35
761
1.64
818
1.54
787
1.85
842
1.75
813
2.07
867
1.98
840
2.32
892
2.24
867
2.59
918

BHP
1.27
1.42
1.58
1.76
1.95
2.17
2.41
2.67
2.95

1.0
RPM
BHP
Medium Static Option
786
1.56
806
1.71
827
1.88
848
2.07
871
2.28
894
2.51
917
2.76
941
3.03
966
3.32

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
1.4
1.6
1.8
2.0
RPM
BHP
RPM
BHP
RPM
BHP
RPM
BHP
Medium Static Option
High Static Option
889
2.18
935
2.52
980
2.87
1022
3.23
907
2.35
953
2.70
997
3.06
1039
3.43
926
2.54
972
2.89
1015
3.26
1056
3.64
946
2.75
991
3.11
1033
3.49
1074
3.88
966
2.98
1010
3.35
1052
3.74
1093
4.14
987
3.23
1031
3.61
1072
4.01
1112
4.421
1009
3.50
1052
3.89
1093
4.30
1032
3.80
1074
4.20
1114
4.61
1054
4.11
1096
4.53
-----

NOTE: For more information, see General Fan Performance Notes on page 87.
Boldface indicates field-- supplied drive is required.
1. Recommend using field-- supplied fan pulley (part no. KR11AZ002) and belt (part no. KR29AF054).

90

FAN PERFORMANCE (cont.)

CFM
3000
3250
3500
3750
4000
4250
4500
4750
5000

CFM
3000
3250
3500
3750
4000
4250
4500
4750
5000

3 PHASE
0.2
RPM
BHP
Field---Supplied Drive1
579
0.70
613
0.85
648
1.03
683
1.23
719
1.45
756
1.71
792
1.99
830
2.31
867
2.66

RPM
660
690
721
753
786
819
853
888
923

1.2
RPM

BHP

RPM

917
938
961
985
1011
1037
1064
1091
1120

1.70
1.93
2.18
2.46
2.76
3.09
3.46
3.85
4.28

970
991
1013
1035
1059
1084
1110
1137
1164

10 TON HORIZONTAL SUPPLY

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.4
0.6
0.8
BHP
RPM
BHP
RPM
Standard Static Option
0.89
732
1.09
799
1.06
760
1.27
823
1.25
788
1.48
850
1.47
817
1.71
877
1.71
848
1.97
905
1.98
879
2.26
934
2.28
910
2.57
964
2.62
943
2.92
995
2.98
976
3.30
1026
AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
1.4
1.6
1.8
BHP
RPM
BHP
RPM
Medium Static Option
1.91
1021
2.13
1070
2.16
1041
2.38
1089
2.42
1062
2.66
1108
2.71
1083
2.97
1129
3.03
1106
3.30
1151
3.38
1130
3.66
1174
3.76
1155
4.06
1198
4.16
1180
4.48
4.61
---

BHP
1.29
1.49
1.71
1.96
2.23
2.53
2.87
3.23
3.63

BHP
2.34
2.61
2.91
3.23
3.58
3.95
4.36
---

1.0
RPM
BHP
Medium Static Option
860
1.50
883
1.71
907
1.95
933
2.21
959
2.50
987
2.81
1015
3.16
1044
3.54
1074
3.95
2.0
RPM
BHP
High Static Option
1117
2.56
1134
2.85
1153
3.15
1173
3.49
1194
3.85
1216
4.24
1239
4.66
-----

NOTE: For more information, see General Fan Performance Notes on page 87.
Boldface indicates field-- supplied drive is required.
1. Recommend using field-- supplied fan pulley (part no. KR11AD912) and belt (part no. KR29AF051).
2. Recommend using field-- supplied motor pulley (part no. KR11HY410).

48TC**12
CFM
3000
3250
3500
3750
4000
4250
4500
4750
5000

CFM
3000
3250
3500
3750
4000
4250
4500
4750
5000

3 PHASE
0.2
RPM

BHP

RPM

616
655
695
736
777
818
860
902
944

0.79
0.96
1.17
1.41
1.68
1.98
2.32
2.69
3.11

689
724
760
797
834
873
912
951
991

1.2
RPM

BHP

939
962
987
1014
1042
1072
1103
1135
1167

1.79
2.03
2.30
2.60
2.93
3.30
3.70
4.14
4.63

10 TON VERTICAL SUPPLY

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.4
0.6
0.8
BHP
RPM
BHP
RPM
Standard Static Option
0.97
757
1.16
821
1.16
788
1.37
849
1.38
821
1.60
879
1.63
855
1.86
910
1.91
889
2.16
942
2.23
925
2.49
976
2.58
962
2.85
1010
2.97
999
3.26
1046
3.40
1037
3.70
1082

BHP
1.36
1.58
1.83
2.10
2.41
2.75
3.13
3.55
4.00

1.0
RPM
BHP
Medium Static Option
882
1.57
907
1.80
934
2.06
963
2.35
993
2.67
1025
3.02
1057
3.41
1091
3.84
1125
4.31

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
1.4
1.6
1.8
2.0
RPM
BHP
RPM
BHP
RPM
BHP
RPM
Medium Static Option
High Static Option
994
2.01
1047
2.24
1098
2.47
1147
1015
2.26
1066
2.50
1115
2.75
1163
1038
2.54
1088
2.80
1135
3.05
1181
1063
2.86
1111
3.12
1157
3.39
1202
1090
3.20
1136
3.48
1180
3.76
1224
1118
3.58
1162
3.87
1205
4.16
1147
4.00
1190
4.29
1232
4.60
1177
4.45
-------------

NOTE: For more information, see General Fan Performance Notes on page 87.
Boldface indicates field-- supplied drive is required.
1. Recommend using field-- supplied motor pulley (part no. KR11HY410).

91

BHP
2.71
3.00
3.32
3.66
4.04
-----

48TC

48TC**12

48TC**14
CFM

3 PHASE
0.2
RPM

0.4
BHP

RPM

12.5 TON HORIZONTAL SUPPLY

Available External Static Pressure (in. wg)
0.6
0.8
BHP
RPM
BHP
RPM

1.0
BHP

Standard Static Option

48TC

3438
3750
4063
4375
4688
5000
5313
5625
5938
6250

CFM
3438
3750
4063
4375
4688
5000
5313
5625
5938
6250

639
683
728
774
820
867
914
962
1009
-

0.98
1.23
1.52
1.85
2.23
2.66
3.15
3.69
4.30
1.2

713
753
794
836
879
923
967
1012
1058
-

1.20
1.47
1.78
2.13
2.53
2.98
3.49
4.05
4.68
-

781
817
855
894
935
976
1018
1061
-

1.43
1.71
2.04
2.41
2.83
3.30
3.83
4.42
-

RPM

BHP

Medium Static Option
843
877
912
949
987
1026
1066
-

1.65
1.96
2.31
2.70
3.14
3.63
4.17
-

901
933
966
1001
1037
1074
1112
-

Available External Static Pressure (in. wg)
1.6
1.8
2.0
RPM
BHP
RPM
BHP
RPM
BHP
RPM
Medium Static Option
High Static Option
1007
2.35
1056
2.59
1103
2.83
1148
1035
2.71
1083
2.97
1129
3.23
1173
1066
3.12
1112
3.39
1157
3.67
1200
1097
3.56
1142
3.86
1186
4.15
1228
1130
4.06
1174
4.37
1216
4.68
1257
1164
4.61
1248
5.27
1288
-

1.88
2.21
2.57
2.98
3.44
3.95
4.52
-

1.4

RPM

BHP

955
985
1017
1050
1084
1120
-

2.12
2.46
2.84
3.27
3.75
4.28
-

BHP
3.08
3.49
3.95
4.45
5.00
5.60
-

NOTE: For more information, see General Fan Performance Notes on page 87.
Boldface indicates field-- supplied drive is required.

48TC**14
CFM
3438
3750
4063
4375
4688
5000
5313
5625
5938
6250

CFM
3438
3750
4063
4375
4688
5000
5313
5625
5938
6250

3 PHASE
0.2

12.5 TON VERTICAL SUPPLY

Available External Static Pressure (in. wg)
0.6
0.8
1.0
RPM
BHP
RPM
BHP
RPM
BHP
RPM
Standard Static Option
Medium Static Option
751
1.32
813
1.54
871
1.76
927
797
1.63
855
1.86
910
2.10
963
844
1.99
898
2.24
951
2.49
1001
892
2.40
943
2.67
993
2.94
1041
941
2.87
990
3.15
1037
3.44
1082
991
3.40
1037
3.70
1082
4.00
1125
1042
4.00
1085
4.32
1128
4.64
1093
4.67
0.4

RPM

BHP

685
736
787
839
891
944
997
1051
-

1.12
1.41
1.75
2.14
2.60
3.11
3.69
4.34
1.2

Available External Static Pressure (in. wg)
1.6
1.8
2.0
RPM
BHP
RPM
BHP
RPM
BHP
RPM
Medium Static Option
High Static Option
1032
2.47
1082
2.72
1130
2.97
1177
1063
2.86
1111
3.12
1157
3.39
1202
1097
3.29
1142
3.57
1186
3.85
1230
1132
3.78
1176
4.08
1218
4.37
1260
1169
4.33
1211
4.64
-

BHP
1.99
2.35
2.75
3.21
3.73
4.31
-

1.4

RPM

BHP

981
1014
1049
1087
1126
1167
-

2.23
2.60
3.02
3.49
4.03
4.63
-

NOTE: For more information, see General Fan Performance Notes on page 87.
Boldface indicates field-- supplied drive is required.

92

BHP
3.23
3.66
4.14
4.68
-

APPENDIX III. FAN PERFORMANCE (cont.)

3 phase
3 phase
3 phase

14

12

08

UNIT

MOTOR/DRIVE
COMBO

0.0

0.5

1.0

MOTOR PULLEY TURNS OPEN
1.5
2.0
2.5
3.0
3.5

4.0

4.5

5.0

Standard Static

747

721

695

670

644

618

592

566

541

515

489

Medium Static

949

927

906

884

863

841

819

798

776

755

733

High Static

1102

1083

1063

1044

1025

1006

986

967

948

928

909

Standard Static

838

813

789

764

739

715

690

665

640

616

591

Medium Static

1084

1059

1035

1010

986

961

936

912

887

863

838

High Static

1240

1218

1196

1175

1153

1131

1109

1087

1066

1044

1022

Standard Static

838

813

789

764

739

715

690

665

640

616

591

Medium Static

1084

1059

1035

1010

986

961

936

912

887

863

838

High Static

1240

1218

1196

1175

1153

1131

1109

1087

1066

1044

1022

NOTE: Do not adjust pulley further than 5 turns open.
- Factory settings

93

48TC

Pulley Adjustment

ELECTRICAL INFORMATION
48TC*D08
V ---Ph---Hz

2 ---Stage Cooling
VOLTAGE
RANGE

48TC

MIN MAX

COMP (Cir 1)

COMP (Cir 2)

OFM (ea)

RLA

LRA

RLA

LRA

WATTS

FLA

208--- 3--- 60

187

253

13.6

83

13.6

83

325

1.5

230--- 3--- 60

187

253

13.6

83

13.6

83

325

1.5

460--- 3--- 60

414

506

6.1

41

6.1

41

325

0.8

575--- 3--- 60

518

633

4.2

33

4.2

33

325

0.6

48TC*D12
V ---Ph---Hz

IFM
Max
Max
TYPE
WATTS AMP Draw
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH

1448
2278
4400
1448
2278
4400
1448
2278
4400
1379
3775
4400

5.5
7.9
15.0
5.5
7.9
15.0
2.7
3.6
7.4
2.5
2.9
5.9

EFF at Full Load

FLA

80%
81%
81%
80%
81%
81%
80%
81%
81%
80%
81%
81%

5.2
7.5
15.0
5.2
7.5
15.0
2.6
3.4
7.4
2.4
2.8
5.6

2 ---Stage Cooling
VOLTAGE
RANGE
MIN MAX

COMP (Cir 1)

COMP (Cir 2)

RLA

LRA

RLA

LRA

WATTS

FLA

187

253

15.6

110

15.9

110

325

1.5

230--- 3--- 60

187

253

15.6

110

15.9

110

325

1.5

460--- 3--- 60

414

506

7.7

52

7.7

52

325

0.8

575--- 3--- 60

518

633

5.8

39

5.7

39

325

0.6

48TC*D14

10 Tons

OFM (ea)

208--- 3--- 60

V ---Ph---Hz

7.5 Tons

IFM
TYPE
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH

Max
Max
WATTS AMP Draw
2120
3775
4400
2120
3775
4400
2120
3775
4400
1390
3775
4400

5.5
10.5
15.0
5.5
10.5
15.0
2.7
4.6
7.4
2.1
2.9
5.9

EFF at Full Load

FLA

80%
81%
81%
80%
81%
81%
80%
81%
81%
80%
81%
81%

5.2
10.0
15.0
5.2
10.0
15.0
2.6
4.4
7.4
2.0
2.8
5.6

2 ---Stage Cooling
VOLTAGE
RANGE
MIN MAX

COMP (Cir 1)

COMP (Cir 2)

12.5 Tons

OFM (ea)

RLA

LRA

RLA

LRA

WATTS

FLA

208--- 3--- 60

187

253

19.0

123

22.4

149

1288

6.2

230--- 3--- 60

187

253

19.0

123

22.4

149

1288

6.2

460--- 3--- 60

414

506

9.7

62

10.6

75

1288

3.1

575--- 3--- 60

518

633

7.4

50

7.7

54

1288

2.5

94

IFM
Max
Max
TYPE
WATTS AMP Draw
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH

2615
3775
4400
2615
3775
4400
2615
3775
4400
3775
3775
4400

7.9
10.5
15.0
7.9
10.5
15.0
3.6
4.6
7.4
2.9
2.9
5.9

EFF at Full Load

FLA

81%
81%
81%
81%
81%
81%
81%
81%
81%
81%
81%
81%

7.5
10.0
15.0
7.5
10.0
15.0
3.4
4.4
7.4
2.8
2.8
5.6

NOM.
V ---Ph---Hz

IFM
TYPE

48TC*D08

208/230--- 3--- 60
460--- 3--- 60
575--- 3--- 60

48TC*D12

208/230--- 3--- 60
460--- 3--- 60
575--- 3--- 60

48TC*D14

208/230--- 3--- 60
460--- 3--- 60
575--- 3--- 60

STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH
STD
MED
HIGH

NO C.O. or UNPWRD C.O.
NO P.E.
w/ P.E. (pwrd fr/ unit)
DISC. SIZE
DISC. SIZE
MCA
MOCP
MCA
MOCP
FLA
LRA
FLA
LRA
43.6
50
46
198
47.4
60
51
202
45.9
50
49
235
49.7
60
53
239
0.48
3.8
53.8
60
58
261
57.6
70
62
265
20.1
25
21
97
21.9
25
23
99
20.9
25
22
116
22.7
25
24
118
0.25
1.8
25.3
30
27
129
27.1
30
29
131
14.8
20
16
79
18.6
20
20
83
15.2
20
16
94
19.0
25
21
98
0.24
3.8
18.3
20
19
108
22.1
25
24
112
48.5
60
51
263
52.3
60
56
267
53.3
60
57
306
57.1
70
61
310
0.48
3.8
58.3
70
62
315
62.1
70
67
319
23.7
30
25
125
25.5
30
27
127
25.5
30
27
147
27.3
30
29
149
0.25
1.8
28.5
35
31
151
30.3
35
33
153
17.9
20
19
95
21.7
25
23
99
18.7
25
20
106
22.5
25
24
110
0.24
3.8
21.5
25
23
120
25.3
30
27
124
65.5
80
69
365
69.3
80
73
369
0.48
3.8
68.0
80
72
382
71.8
80
76
386
Model not available due to high amperage draw.
31.7
40
33
183
33.5
40
35
185
32.7
40
35
192
34.5
45
37
194
0.25
1.8
35.7
45
38
196
37.5
45
40
198
24.0
30
25
144
27.8
30
30
148
24.0
30
25
144
27.8
30
30
148
0.24
3.8
26.8
30
29
158
30.6
35
33
162
COMBUSTION
FAN MOTOR
FLA

POWER
EXHAUST
FLA

LEGEND:
CO
--- Convenient outlet
DISC
--- Disconnect
FLA
--- Full load amps
IFM
--- Indoor fan motor
LRA
--- Locked rotor amps
MCA
--- Minimum circuit amps
MOCP
--- Maximum over current protection
PE
--- Power exhaust
UNPWRD CO --- Unpowered convenient outlet
NOTES:
1. In compliance with NEC requirements for multimotor and
combination load equipment (refer to NEC Articles 430 and
440), the overcurrent protective device for the unit shall be
fuse or HACR breaker. Canadian units may be fuse or circuit
breaker.
2. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply
voltage is greater than 2%. Use the following formula to
determine the percentage of voltage imbalance.

Example: Supply voltage is 230-3-60
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =

=

(224 + 231 + 226)
3

=

681
3

227

Determine maximum deviation from average voltage.
(AB) 227 – 224 = 3 v
(BC) 231 – 227 = 4 v
(AC) 227 – 226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance

= 100 x

4
227

= 1.76%
% Voltage Imbalance

= 100 x

max voltage deviation from average voltage
average voltage

This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.

95

48TC

UNIT

MCA/MOCP DETERMINATION NO C.O. OR UNPWRD C.O.

APPENDIX IV. WIRING DIAGRAM LIST
Wiring Diagrams

All

VOLTAGE
208/230---3---60
460---3---60
575---3---60
208/230---3---60
460---3---60
575---3---60
208/230---3---60
460---3---60
575---3---60
PremierLink*

48TC
CONTROL
48TM501325
48TM501325
48TM501325
48TM501325
48TM501325
48TM501325
48TM501379
48TM501379
48TM501379
48TM500984

All

RTU ---MP*

48TM500988

SIZE
D08

D12

48TC

D14

POWER
48TM501326
48TM501326
48TM501327
48TM501326
48TM501326
48TM501327
48TM501380
48TM501380
48TM501381

NOTE: Component arrangement on Control; Legend on Power Schematic
* PremierLink and RTU-- MP control labels overlay a portion of the base unit control label. The base unit label drawing and the control option drawing are
required to provide a complete unit control diagram.

96

48TC

APPENDIX V. MOTORMASTER SENSOR LOCATIONS

Fig. 86 - 48TC*D08-- D12 Outdoor Circuiting

C09158

NOTE: The low ambient kit for the 12.5 ton unit utilizes a pressure transducer, and therefore there is no Motormaster
temperature sensor location for this unit.

Copyright 2009 Carrier Corp. S 7310 W. Morris St. S Indianapolis, IN 46231

Printed in U.S.A.

Edition Date: 7/09

Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.

97

Catalog No: 48TC-3SM
Replaces: NEW

UNIT START-UP CHECKLIST
I. PRELIMINARY INFORMATION:
MODEL NO.:
DATE:

SERIAL NO: _____________________________________
TECHNICIAN: ___________________________________
BUILDING LOCATION:____________________________

______________

48TC

II. PRE-START-UP (insert check mark in box as each item is completed):
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VERIFY THAT ALL PACKAGING MATERIALS HAVE BEEN REMOVED FROM UNIT
VERIFY THAT CONDENSATE CONNECTION IS INSTALLED PER INSTALLATION INSTRUCTIONS
VERIFY THAT FLUE HOOD IS INSTALLED
CHECK ALL ELECTRICAL CONNECTIONS AND TERMINALS FOR TIGHTNESS
CHECK TO ENSURE NO WIRES ARE TOUCHING REFRIGERANT TUBING OR SHARP EDGES
CHECK GAS PIPING FOR LEAKS
CHECK THAT RETURN--AIR FILTER IS CLEAN AND IN PLACE
VERIFY THAT UNIT INSTALLATION IS LEVEL
CHECK FAN WHEEL AND PROPELLER FOR LOCATION IN HOUSING/ORIFICE AND VERIFY SETSCREW IS TIGHT
VERIFY PULLEY ALIGNMENT AND BELT TENSION ARE CORRECT

III. START-UP
ELECTRICAL
SUPPLY VOLTAGE

L1-L2

L2-L3

L3-L1

COMPRESSOR 1

L1

L2

L2

COMPRESSOR 2

L1

L2

L2

INDOOR FAN AMPS

L1

L2

L2

TEMPERATURES
OUTDOOR-AIR TEMPERATURE

DB

WB

RETURN-AIR TEMPERATURE

DB

WB

COOLING SUPPLY AIR

DB

WB

GAS HEAT SUPPLY AIR

DB

PRESSURES
GAS INLET PRESSURE

IN. WG

GAS MANIFOLD PRESSURE
REFRIGERANT SUCTION
REFRIGERANT DISCHARGE

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CIR 1

IN. WG (LOW FIRE)

IN. WG (HI FIRE)

PSIG

TEMP _F

CIR 2

PSIG

TEMP _F

CIR 1

PSIG

TEMP _F

CIR 2

PSIG

TEMP _F

VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS
VERIFY THAT 3--PHASE SCROLL COMPRESSORS ARE ROTATING IN CORRECT DIRECTION

98



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