Carrier 48Vtn Users Manual 48VT 05SI

48VT(N) 48VT-05SI

48VT(N) to the manual d54aa3ff-51b5-4b7c-880c-3404ca198c64

2015-01-24

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48VT(N) ---A

Performancet14 SEER Single---Packaged HYBRID HEAT®

Dual Fuel System with Puronr(R---410A) Refrigerant

Single And Three Phase

2 --- 5 N o m i n a l To n s ( S i z e s 2 4 --- 6 0 )

Installation Instructions

NOTE: Read the entire instruction manual before starting the

installation.

NOTE: Installer: Make sure the Owner’s Manual and Service

Instructions are left with the unit after installation.

TABLE OF CONTENTS

PAGE

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

INTRODUCTION 2...................................

RECEIVING AND INSTALLATION 2--13.................

Check Equipment 2..................................

Identify Unit 2....................................

Inspect Shipment 2.................................

Provide Unit Support 2...............................

Roof Curb 2......................................

Slab Mount 2.....................................

Field Fabricate Ductwork 2............................

Provide Clearances 2.................................

Rig and Place Unit 6.................................

Connect Condensate Drain 7...........................

Install Flue Hood 7...................................

Install Gas Piping 7..................................

Install Duct Connections 8.............................

Configuring Units for Downflow (Vertical)

Discharge 8......................................

Install Electrical Connections 11........................

High--Voltage Connections 11........................

Special Procedures for 208--V Operation 11..............

Control Voltage Connections 11.......................

Balance Point Setting Thermidistat or Hybrid Heat

Thermostat 12....................................

Transformer Protection 12...........................

PRE--START--UP 12...................................

START--UP 13--17.....................................

Check for Refrigerant Leaks 13.........................

Unit Sequence of Operation 13.........................

Start--Up Heating and Make Adjustments 13...............

Checking Heating Control 14.........................

Check Gas Input 14................................

Adjust Gas Input 14................................

Check Burner Flame 15.............................

Start--Up Cooling and Make Adjustments 16...............

Checking Cooling Control Operation 16................

Checking and Adjusting Refrigerant 16.................

Indoor Airflow and Airflow Adjustments 16.............

Continuous Fan Operation 17........................

MAINTENANCE 27--33................................

Air Filter 27........................................

Indoor Blower and Motor 27...........................

Flue Gas Passageways 28..............................

Limit Switch 28.....................................

Burner Ignition 28...................................

Main Burners 28....................................

Outdoor Coil, Indoor Coil, & Condensate Drain Pan 28......

A09042

Fig. 1 -- Unit 48VT--A

Outdoor Fan 29.....................................

Electrical Controls and Wiring 29.......................

Refrigerant Circuit 29.................................

Gas Input 30........................................

Indoor Airflow 30...................................

Check Defrost Thermostat 30...........................

PuronRItems 30....................................

TROUBLESHOOTING 33..............................

START--UP CHECKLIST 33............................

SAFETY CONSIDERATIONS

Improper installation, adjustment, alteration, service maintenance,

or use can cause explosion, fire, electrical shock, or other

conditions which may cause death, personal injury, or property

damage. Consult a qualified installer, service agency, or your

distributor or branch for information or assistance. The qualified

installer or agency must use factory--authorized kits or accessories

when modifying this product. Refer to the individual instructions

packaged with the kits or accessories when installing.

Follow all safety codes. Wear safety glasses, protective clothing,

and work gloves. Have a fire extinguisher available. Read these

instructions thoroughly and follow all warnings or cautions

included in literature and attached to the unit. consult local

building codes, the current editions of the National Fuel Gas Code

(NFGC) NFPA 54/ANSI Z223.1, and the National Electrical Code

(NEC) NFPA 70.

In Canada refer to the current editions of the National Standards of

Canada CAN/CSA--B149.1 and .2 Natural Gas and Propane

Installation codes, and Canadian Electrical Code CSA C22.1

Recognize safety information. This is the safety--alert symbol .

When you see this symbol on the unit and in instructions or manu-

als, be alert to the potential for personal injury. Understand these

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 hazards which could result in per-

sonal injury or death. CAUTION is used to identify unsafe practic-

es which may result in minor personal injury or product and prop-

erty damage. NOTE is used to highlight suggestions which will

result in enhanced installation, reliability, or operation.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal

injury or death.

Before installing or servicing system, always turn off main

power to system. There may be more than one disconnect

switch. Turn off accessory heater power switch if

applicable. TAG THE DISCONNECT SWITCH WITH A

SUITABLE WARNING LABEL.

!WARNING

FIRE, EXPLOSION, ELECTRICAL SHOCK AND

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal

injury, death or property damage.

A qualified installer or agency must use only

factory--authorized kits or accessories when modifying this

product.

WARNING

CUT HAZARD

Failure to follow this caution may result in personal injury.

When removing access panels (see Fig. 19) or performing

maintenance functions inside your unit, be aware of sharp

sheet metal parts and screws. Although special care is taken

to reduce sharp edges to a minimum, be extremely careful

when handling parts or reaching into the unit.

CAUTION

INTRODUCTION

The 48VT--A unit (see Fig. 1) is a fully self--contained,

combination Category I gas heating/electric heating and cooling

unit designed for outdoor installation (See Fig. 2 and 3 for unit

dimensions). All unit sizes have return and discharge openings for

both horizontal and downflow configurations, and are factory

shipped with all downflow duct openings covered. Units may be

installed either on a rooftop, a cement slab, or directly on the

ground, if local codes permit (See Fig. 4 for roof curb dimensions).

Models with an N in the fifth position of the model number are

dedicated Low NOx units designed for California installations.

These models meet the California maximum oxides of nitrogen

(NOx) emissions requirements of 40 nanograms/joule or less as

shipped from the factory and must be installed in California Air

Quality Management Districts or any other regions in North

America where a Low NOx rule exists.

RECEIVING AND INSTALLATION

Step 1 — Check Equipment

IDENTIFY UNIT

The unit model number and serial number are stamped on the unit

information plate. Check this information against shipping papers.

INSPECT SHIPMENT

Inspect for shipping damage before removing packaging materials.

If unit appears to be damaged or is torn loose from its anchorage,

have it examined by transportation inspectors before removal.

Forward claim papers directly to transportation company.

Manufacturer is not responsible for any damage incurred in transit.

Check all items against shipping list. Immediately notify the

nearest equipment distribution office if any item is missing. To

prevent loss or damage, leave all parts in original packages until

installation.

Step 2 — Provide Unit Support

For hurricane tie downs, contact distributor for details and PE

(Professional Engineering) Certificate if required.

ROOF CURB

Install accessory roof curb in accordance with instructions shipped

with curb (See Fig. 4). Install insulation, cant strips, roofing, and

flashing. Ductwork must be attached to curb.

IMPORTANT: The gasketing of the unit to the roof curb is

critical for a water tight seal. Install gasketing material supplied

with the roof curb. Improperly applied gasketing also can result in

air leaks and poor unit performance.

Curb should be level to within 1/4 in. (6 mm). This is necessary for

unit drain to function properly. Refer to accessory roof curb

installation instructions for additional information as required.

SLAB MOUNT

Place the unit on a solid, level concrete pad that is a minimum of 4

in. (102 mm) thick with 2 in. (51 mm) above grade. The slab

should be flush on the compressor end of the unit (to allow

condensate drain installation) and should extend 2 in. (51 mm) on

the three remaining sides of the unit. Do not secure the unit to the

slab except when required by local codes.

Step 3 — Field Fabricate Ductwork

Secure all ducts to roof curb and building structure on vertical

discharge units. Do not connect ductwork to unit. For horizontal

applications, unit is provided with flanges on the horizontal

openings. All ductwork should be secured to the flanges. Insulate

and weatherproof all external ductwork, joints, and roof openings

with counter flashing and mastic in accordance with applicable

codes.

Ducts passing through an unconditioned space must be insulated

and covered with a vapor barrier.

If a plenum return is used on a vertical unit, the return should be

ducted through the roof deck to comply with applicable fire codes.

Read unit rating plate for any required clearances around ductwork.

Cabinet return--air static shall not exceed --.25 IN. W.C.

Step 4 — Provide Clearances

The required minimum operating and service clearances are shown

in Fig. 2 and 3.

IMPORTANT: Do not restrict outdoor airflow. An air restriction

at either the outdoor--air inlet or the fan discharge may be

detrimental to compressor life.

The condenser fan pulls air through the condenser coil and

discharges it through the top grille. Be sure that the fan discharge

does not recirculate to the condenser coil. Do not locate the unit in

either a corner or under an overhead obstruction. The minimum

clearance under a partial overhang (such as a normal house

overhang) is 48--in. (1219 mm) above the unit top. The maximum

horizontal extension of a partial overhang must not exceed 48--in.

(1219 mm).

Do not place the unit where water, ice, or snow from an overhang

or roof will damage or flood the unit. Do not install the unit on

carpeting or other combustible materials. The unit may be installed

on wood flooring or on Class A, B, or C roof covering materials.

48VT--A

A09146

Fig. 2 -- 48VT--A24--30 Unit Dimensions

48VT--A

A09147

Fig. 3 -- 48VT--A36--60 Unit Dimensions

48VT--A

LARGE CURB

SMALL CURB

ROOF CURB DETAIL

Wood nailer*

Roofcurb*

Insulation

(field supplied)

*Provided with roofcurb

Cant strip

field supplied

Roofing material

field supplied

Flashing field

supplied

HVAC unit

base rails

Roofcurb

Sealing

Gasket

HVAC unit

basepan

Anchor screw

A09090

A09095

A09110

A09111

UNIT SIZE CATALOG

NUMBER

IN. (mm)

IN. (mm)*

IN. (mm)

Small CPRFCURB010A00 11 (279) 10 (254)

16 (406) 47.8 (1214)

32.4 (822)

2.7 (69)

CPRFCURB011A00 14 (356)

Large CPRFCURB012A00 11 (279) 14 (356) 43.9 (1116)

CPRFCURB013A00 14 (356)

NOTES:

1. Roof curb must be set up for unit being installed.

2. Seal strip must be applied, as required, to unit being installed.

3. Roof curb is made of 16--gauge steel.

4. Attach ductwork to curb (flanges of duct rest on curb).

5. Insulated panels: 1--in. (25.4 mm) thick fiberglass 1 lb. density.

IMPORTANT: Do not install large base pan HYBRID HEAT

units onto the small base pan (common curb). The center of gravity

on a large base pan HYBRID HEAT unit could overhang the curb

causing an unsafe condition. Before installing any large base pan

unit onto the common curb, check the “Y” distance in the product

literature dimensional drawing to ensure that “Y” is greater than 14

in. (356 mm). Do not install any large base pan unit onto the

common curb with a “Y” dimension (center of gravity) less than 14

in. (356 mm).

Fig. 4 -- Roof Curb Dimensions

48VT--A

ACCESS PANELS MUST BE IN PLACE WHEN RIGGING.

PANNEAUX D'ACCES DOIT ÊTRE EN PLACE POUR MANIPULATION.

50CY502286 2.0

CAUTION - NOTICE TO RIGGERS

PRUDENCE - AVIS AUX MANIPULATEUR

Use top skid as spreader bar. / Utiliser la palette du haut comme barre de répartition

SEAL STRIP MUST BE IN

PLACE BEFORE PLACING

UNIT ON ROOF CURB

DUCTS

DETAIL A

VOIR DÉTAIL A

MINIMUM HEIGHT: 36" (914.4 mm)

HAUTEUR MINIMUM

UNIT HEIGHT

HAUTEUR D'UNITÉ

SEE DETAIL A

VOIR DÉTAIL A

BANDE SCELLANT DOIT ÊTRE

EN PLACE AVANT DE PLACER

L'UNITÉ SUR LA BASE DE TOIT

A09051

Unit 24 30 Unit 36 42 48 60

lb kg lb kg lb kg lb kg lb kg lb kg

Rigging

Weight 368 167 378 171 Rigging

Weight 450 204 491 223 513 233 543 246

NOTE: See dimensional drawing for corner weight distribution.

Fig. 5 -- 48VT--A Suggested Rigging

Step 5 — Rig and Place Unit

PERSONAL INJURY OR PROPERTY DAMAGE

HAZARD

Failure to follow this warning could result in personal

injury, death or property damage.

When installing the unit on a rooftop, be sure the roof will

support the additional weight.

!WARNING

Rigging and handling of this equipment can be hazardous for

many reasons due to the installation location (roofs, elevated

structures, etc.).

Only trained, qualified crane operators and ground support staff

should handle and install this equipment.

When working with this equipment, observe precautions in the

literature, on tags, stickers, and labels attached to the equipment,

and any other safety precautions that might apply.

Training for operators of the lifting equipment should include, but

not be limited to, the following:

1. Application of the lifter to the load, and adjustment of the

lifts to adapt to various sizes or kinds of loads.

2. Instruction in any special operation or precaution.

3. Condition of the load as it relates to operation of the lifting

kit, such as balance, temperature, etc.

Follow all applicable safety codes. Wear safety shoes and work

gloves.

Inspection

Prior to initial use, and at monthly intervals, all rigging shackles,

clevis pins, and straps should be visually inspected for any

damage, evidence of wear, structural deformation, or cracks.

Particular attention should be paid to excessive wear at hoist

hooking points and load support areas. Materials showing any kind

of wear in these areas must not be used and should be discarded.

UNIT FALLING HAZARD

Failure to follow this warning could result in personal

injury or death.

Never stand beneath rigged units or lift over people.

!WARNING

PROPERTY DAMAGE HAZARD

Failure to follow this warning could result in personal

injury/death or property damage.

When straps are taut, the clevis should be a minimum of 36

in. (914 mm) above the unit top cover.

!WARNING

Rigging/Lifting of Unit (See Fig. 5)

Lifting holes are provided in base rails as shown in Fig. 2 and 3.

1. Leave top shipping skid on the unit for use as a spreader bar

to prevent the rigging straps from damaging the unit. If the

skid is not available, use a spreader bar of sufficient length

to protect the unit from damage.

2. Attach shackles, clevis pins, and straps to the base rails of

the unit. Be sure materials are rated to hold the weight of the

unit (See Fig. 5).

48VT--A

3. Attach a clevis of sufficient strength in the middle of the

straps. Adjust the clevis location to ensure unit is lifted level

with the ground.

After the unit is placed on the roof curb or mounting pad, remove

the top skid.

Step 6 — Connect Condensate Drain

NOTE: When installing condensate drain connection be sure to

comply with local codes and restrictions.

Model 48VT--A disposes of condensate water through a 3/4 in.

NPT fitting which exits through the compressor access panel (See

Fig. 2 and 3 for location).

Condensate water can be drained directly onto the roof in rooftop

installations (where permitted) or onto a gravel apron in ground

level installations. Install a field--supplied condensate trap at end

of condensate connection to ensure proper drainage. Make sure that

the outlet of the trap is at least 1 in. (25 mm) lower than the

drain--pan condensate connection to prevent the pan from

overflowing (See Fig. 6). Prime the trap with water. When using a

gravel apron, make sure it slopes away from the unit.

If the installation requires draining the condensate water away

from the unit, install a 2--in. (51 mm) trap at the condensate

connection to ensure proper drainage (See Fig. 6). Make sure that

the outlet of the trap is at least 1 in. (25 mm) lower than the

drain--pan condensate connection. This prevents the pan from

overflowing.

Prime the trap with water. Connect a drain tube -- using a minimum

of 3/4--in. PVC or 3/4--in. copper pipe (all field--supplied) -- at the

outlet end of the 2--in. (51 mm) trap. Do not undersize the tube.

Pitch the drain tube downward at a slope of at least 1--in. (25 mm)

for every 10 ft (3 m) of horizontal run. Be sure to check the drain

tube for leaks.

TRAP

OUTLET

1-in. (25 mm) min.

2-in. (51 mm) min.

A09052

Fig. 6 -- Condensate Trap

Step 7 — Install Flue Hood

The flue assembly is secured and shipped in the return air duct.

Remove duct cover to locate the assembly (See Fig. 8).

NOTE: Dedicated low NOx models MUST be installed in

California Air Quality Management Districts where a Low NOx

rule exists.

These models meet the California maximum oxides of nitrogen

(NOx) emissions requirements of 40 nanograms/joule or less as

shipped from the factory.

NOTE: Low NOx requirements apply only to natural gas

installations.

CARBON MONOXIDE POISONING HAZARD

Failure to follow this warning could result in personal

injury or death.

The venting system is designed to ensure proper venting.

The flue hood assembly must be installed as indicted in this

section of the unit installation instructions.

!WARNING

Install the flue hood as follows:

1. This installation must conform with local building codes

and with the National Fuel Gas Code (NFGC) NFPA 54 /

ANSI Z223.1, (in Canada, CAN/CGA B149.1, and

B149.2) latest revision. Refer to Provincial and local

plumbing or wastewater codes and other applicable local

codes.

2. Remove flue hood from shipping location (inside the return

section of the blower compartment--see Fig. 8). Remove the

return duct cover to locate the flue hood. Place flue hood

assembly over flue panel. Orient screw holes in flue hood

with holes in the flue panel.

3. Secure flue hood to flue panel by inserting a single screw on

the top flange and the bottom flange of the hood.

Step 8 — Install Gas Piping

The gas supply pipe enters the unit through the access hole

provided. The gas connection to the unit is made to the 1/2--in.

(12.7 mm) FPT gas inlet on the gas valve.

Install a gas supply line that runs to the heating section. Refer to

Table 2 and the NFGC for gas pipe sizing. Do not use cast--iron

pipe. It is recommended that a black iron pipe is used. Check the

local utility for recommendations concerning existing lines. Size

gas supply piping for 0.5 IN. W.C. maximum pressure drop. Never

use pipe smaller than the 1/2--in. (12.7 mm) FPT gas inlet on the

unit gas valve.

For natural gas applications, the gas pressure at unit gas connection

must not be less than 4.0 IN. W.C. or greater than 13 IN. W.C.

while the unit is operating. For propane applications, the gas

pressure must not be less than 11.0 IN. W.C. or greater than 13 IN.

W.C. at the unit connection.

A 1/8--in. (3.2 mm) NPT plugged tapping, accessible for test gauge

connection, must be installed immediately upstream of the gas

supply connection to the gas valve.

When installing the gas supply line, observe local codes pertaining

to gas pipe installations. Refer to the NFGC NFPA 54/ANSI

Z223.1 latest edition (in Canada, CAN/CGA B149.1).

NOTE: In the state of Massachusetts:

1. Gas supply connections MUST be performed by a licensed

plumber or gas fitter.

2. When flexible connectors are used, the maximum length

shall not exceed 36 in. (915 mm).

3. When lever handle type manual equipment shutoff valves

are used, they shall be T--handle valves.

4. The use of copper tubing for gas piping is NOT approved

by the state of Massachusetts.

In the absence of local building codes, adhere to the following

pertinent recommendations:

1. Avoid low spots in long runs of pipe. Grade all pipe 1/4 in.

(6.35 mm) for every 15 ft (4.6 m) of length to prevent traps.

Grade all horizontal runs downward to risers. Use risers to

connect to heating section and to meter.

2. Protect all segments of piping system against physical and

thermal damage. Support all piping with appropriate straps,

hangers, etc. Use a minimum of one hanger every 6 ft (1.8

m). For pipe sizes larger than 1/2 in., (12.7 mm) follow

recommendations of national codes.

3. Apply joint compound (pipe dope) sparingly and only to

male threads of joint when making pipe connections. Use

only pipe dope that is resistant to action of liquefied

petroleum gases as specified by local and/or national codes.

Never use Teflon tape.

4. Install sediment trap in riser leading to heating section (See

Fig. 7). This drip leg functions as a trap for dirt and

condensate.

48VT--A

OUT TEE

NIPPLE

CAP

C99020

Fig. 7 -- Sediment Trap

5. Install an accessible, external, manual main shutoff valve in

gas supply pipe within 6 ft (1.8 m) of heating section.

6. Install ground--joint union close to heating section between

unit manual shutoff and external manual main shut--off

valve.

7. Pressure test all gas piping in accordance with local and

national plumbing and gas codes before connecting piping

to unit.

NOTE: Pressure test the gas supply system after the gas supply

piping is connected to the gas valve. The supply piping must be

disconnected from the gas valve during the testing of the piping

systems when test pressure is in excess of 0.5 psig. Pressure test the

gas supply piping system at pressures equal to or less than 0.5 psig.

The unit heating section must be isolated from the gas piping

system by closing the external main manual shutoff valve and

slightly opening the ground--joint union.

FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal injury,

death and/or property damage.

--Connect gas pipe to unit using a backup wrench to avoid

damaging gas controls.

--Never purge a gas line into a combustion chamber. Never

test for gas leaks with an open flame. Use a commercially

available soap solution made specifically for the detection of

leaks to check all connections.

--Use proper length of pipe to avoid stress on gas control

manifold.

--If a flexible connector is required or allowed by authority

having jurisdiction, black iron pipe shall be installed at

furnace gas valve and extend a minimum of 2 in. (51 mm)

outside furnace casing.

--If codes allow a flexible connector, always use a new

connector. do not use a connector which has previously

serviced another gas appliance.

!WARNING

8. Check for gas leaks at the field--installed and

factory--installed gas lines after all piping connections have

been completed. Use a commercially available soap solution

made specifically for the detection of leaks (or method

specified by local codes and/or regulations).

Step 9 — Install Duct Connections

The unit has duct flanges on the supply-- and return--air openings

on the side and bottom of the unit. For downshot applications, the

ductwork connects to the roof curb (See Fig. 2 and 3 for

connection sizes and locations).

Configuring Units for Downflow (Vertical) Discharge

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Before installing or servicing system, always turn off main

power to system. There may be more than one disconnect

switch. Tag the disconnect switch with a suitable warning

label.

!WARNING

1. Open all electrical disconnects before starting any service

work.

2. Remove horizontal (metal) duct covers to access vertical

(downflow) discharge duct knockouts in unit basepan. (See

Fig. 8.)

3. Starting in a corner as shown in Fig. 9, score the panel in

both directions from the corner. Tap the panel out from the

scored corner using a small hammer. Be careful and not

damage any other part of the unit.

4. If unit ductwork is to be attached to vertical opening flanges

on the unit base (jackstand applications only), do so at this

time.

PROPERTY DAMAGE HAZARD

Failure to follow this caution may result in property damage.

Collect ALL screws that were removed. Do not leave screws

on rooftop as permanent damage to the roof may occur.

CAUTION

5. It is recommended that the base insulation around the

perimeter of the vertical return--air opening be secured to

the base with aluminum tape. Applicable local codes may

require aluminum tape to prevent exposed fiberglass.

6. Reinstall both horizontal duct covers. Ensure opening is

air-- and watertight.

7. After completing unit conversion, perform all safety checks

and power up unit.

NOTE: The design and installation of the duct system must be in

accordance with the standards of the NFPA for installation of

nonresidence--type air conditioning and ventilating systems, NFPA

90A or residence--type, NFPA 90B; and/or local codes and

ordinances.

Adhere to the following criteria when selecting, sizing, and

installing the duct system:

1. Units are shipped for horizontal duct installation (by

removing duct covers).

2. Select and size ductwork, supply--air registers, and

return--air grilles according to American Society of Heating,

Refrigeration and Air Conditioning Engineers (ASHRAE)

recommendations.

3. Use flexible transition between rigid ductwork and unit to

prevent transmission of vibration. The transition may be

screwed or bolted to duct flanges. Use suitable gaskets to

ensure weather tight and airtight seal.

48VT--A

Table 1 – Physical Data -- Unit 48VT--A

UNIT SIZE 024040 024060 030040 030060 036060 036090 042060 042090

NOMINAL CAPACITY --- ton 2 2 2 --- 1 / 2 2 --- 1 / 2 3 3 3 --- 1 / 2 3 --- 1 / 2

SHIPPING WEIGHT --- lb.

(kg)

368

167

368

167

378

171

378

171

450

204

450

204

491

223

491

223

COMPRESSORS Scroll

Quantity 1

REFRIGERANT (R--- 410A)

Quantity ---lb

(kg)

9.5

4.3

9.5

4.3

10.5

4.8

10.5

4.8

9.0

4.1

9.0

4.1

14.0

6.4

14.0

6.4

REFRIGERANT METERING

DEVICE Indoor--- TXV, Outdoor--- Accurater

OUTDOOR ORIFICE

in. (qty)

(mm)

0.032 (2)

.81

0.032 (2)

.81

0.038 (2)

.97

0.038 (2)

.97

0.040 (2)

1.02

0.040 (2)

1.02

0.038 (Left OD Coil)

0.040 (Right OD Coil)

.97/1.02

OUTDOOR COIL

Rows...Fins/in.

F a c e A r e a --- s q f t

2...21

13.6

2...21

13.6

2...21

15.4

2...21

15.4

2...21

13.6

2...21

13.6

2...21

19.4

2...21

19.4

OUTDOOR FAN

Nominal Cfm

Diameter --- in.

(mm)

Motor Hp (Rpm)

2500

559

1/8 (825)

2500

559

1/8 (825)

2600

559

1/8 (825)

2600

559

1/8 (825)

3000

559

1/4 (1100)

3000

559

1/4 (1100)

3500

559

1/8 (825)

3500

559

1/8 (825)

INDOOR COIL

Rows...Fins/in.

F a c e A r e a --- s q f t

3...17

3.7

3...17

3.7

3...17

3.7

3...17

3.7

3...17

4.7

3...17

4.7

3...17

4.7

3...17

4.7

INDOOR BLOWER

Nominal Cooling Airflow --- (CFM)

S i z e --- i n .

(mm)

M o t o r --- h p

800

10x10

254x254

1/2

800

10x10

254x254

1/2

1000

10x10

254x254

1/2

1000

10x10

254x254

1/2

1200

11x10

279x254

3/4

1200

11x10

279x254

3/4

1400

11x10

279x254

3/4

1400

11x10

279x254

3/4

FURNACE SECTION*

Burner Orifice

Natural Gas Qty...Drill Size

Propane GasQty...Drill Size

2...44

2...55

2...38

2...53

2...44

2...55

2...44

2...53

2...38

2...53

3...38

3...53

2...38

2...53

3...38

3...53

HIGH---PRESSURE SWITCH

( p s i g ) C u t --- o u t

Reset (Auto)

650 +/--- 15

420 +/--- 25

L O S S --- O F --- C H A R G E /

LOW--- PRESSURE SWITCH

(Liquid Line) (psig)

C u t --- o u t

Reset (auto)

2 0 + / --- 5

45 +/--- 10

RETURN --- AIR FILTERS † }

Throwaway (in.)

(mm)

20x20x1

508x508x25

20x24x1

508x610x25

24x30x1

610x762x25

*Based on altitude of 0 to 2000 ft (0---610 m).

{Required filter sizes shown are based on the larger of the ARI (Air Conditioning and Refrigeration Institute) rated cooling airflow or the heating airflow velocity of

300 ft/minute for high ---capacity type. Air filter pressure drop for non ---standard filters must not exceed 0.08 IN. W.C.

}If using accessory filter rack refer to filter rack installation instructions for correct filter size and quantity.

Horizontal Duct Covers

A09076

Basepan

Downflow

(Vertical)

Supply

Knockout

Basepan

Downflow

(Vertical)

Return

Knockout

A09077

Fig. 8 -- Supply and Return Duct Opening

221

334

1. Score groove in corner 1 in both directions as far as you can reach.

2. Starting in corner 1, tap-out all sides with a small hammer. Be careful

not to damage any other part of unit.

3. If side from corner 3 to 4 is not accessible due to heat exchanger,

pivot panel up and down by hand until remaining side breaks off.

INSTRUCTIONS FOR REMOVING DOWNSHOT PANELS

A09054

Fig. 9 -- Vertical (Downflow) Discharge Duct Knockouts

48VT--A

Table 1 -- Physical Data -- Unit 48VT--A Cont’d)

UNIT SIZE 048090 048115 048130 060090 060115 060130

NOMINAL CAPACITY --- ton 444555

SHIPPING WEIGHT --- lb

(kg)

513

233

513

233

513

233

543

246

543

246

546

246

COMPRESSORS Scroll

Quantity 1

REFRIGERANT (R --- 410A)

Quantity --- lb

(kg )

17.0

7.7

17.0

7.7

17.0

7.7

16.0

7.3

16.0

7.3

16.0

7.3

REFRIGERANT METERING DEVICE TXV

OUTDOOR ORIFICE---in. (qty)

(mm)

0.040 (2)

1.02

0.049 (2)

1.24

OUTDOOR COIL

Rows...Fins --- in.

F a c e A r e a --- s q f t

2...21

19.4

2...21

19.4

2...21

19.4

2...21

23.3

2...21

23.3

2...21

23.3

OUTDOOR FAN

Nominal Cfm

Diameter---in.

(mm)

M o t o r H p --- R p m

3500

559

1/4 (1100)

3500

559

1/4 (1100)

3500

559

1/4 (1100)

3800

559

1/3 (1100)

3800

559

1/3 (1100)

3800

559

1/3 (1100)

INDOOR COIL

Rows...Fins --- in.

F a c e A r e a --- s q f t

3...17

5.7

3...17

5.7

3...17

5.7

4...17

5.7

4...17

5.7

4...17

5.7

INDOOR BLOWER

Nominal Cooling Airflow--- (CFM)

S i z e --- i n .

(mm)

M o t o r --- h p

1600

11x10

279x254

1.0

1600

11x10

279x254

1.0

1600

11x10

279x254

1.0

1750

11x10

279x254

1.0

1750

11x10

279x254

1.0

1750

11x10

279x254

1.0

FURNACE SECTION*

Burner Orifice

Natural Gas Qty...Drill Size

Propane GasQty...Drill Size

3...38

3...53

3...33

3...51

3...31

3...49

3...38

3...53

3...33

3...51

3...31

3...49

HIGH --- PRESSURE SWITCH (psig)

C u t --- o u t

Reset (Auto)

650 +/---15

420 +/---25

L O S S --- O F --- C H A R G E /

LOW --- PRESSURE SWITCH

(Liquid Line) (psig)

C u t --- o u t

Reset (auto)

2 0 + / --- 5

45 +/---10

RETURN--- AIR FILTERS †

Throwaway (in.)

(mm)

24x36x1

(610x914x25)

*Based on altitude of 0 to 2000 ft (0---610 m).

{Required filter sizes shown are based on the larger of the ARI (Air Conditioning and Refrigeration Institute) rated cooling airflow or the heating airflow velocity of

300 ft/minute for high ---capacity type. Air filter pressure drop for non ---standard filters must not exceed 0.08 IN. W.C.

}If using accessory filter rack refer to filter rack installation instructions for correct filter size and quantity.

Table 2 – Maximum Gas Flow Capacity*

NOMINAL

IRON

PIPE, SIZE

(IN.)

INTERNAL

DIAMETER

(IN.)

LENGTH OF PIPE, FT (m)†

(3.0)

(6.1)

(9.1)

(12.2)

(15.2)

(18.3)

(21.3)

(24.4)

(27.4)

100

(30.5)

125

(31.1)

150

(45.7)

175

(53.3)

200

(61.0)

1/2 .622 175 120 97 82 73 66 61 57 53 50 44 40 — —

3/4 .824 360 250 200 170 151 138 125 118 110 103 93 84 77 72

11.049 680 465 375 320 285 260 240 220 205 195 175 160 145 135

1 --- 1 / 4 1.380 1400 950 770 600 580 530 490 460 430 400 360 325 300 280

1 --- 1 / 2 1.610 2100 1460 1180 990 900 810 750 690 650 620 550 500 460 430

* Capacity of pipe in cu ft of gas per hr for gas pressure of 0.5 psig or less. Pressure drop of 0.5--IN. W.C. (based on a 0.60 specific gravity gas). Refer to Table 2

and the NFGC NFPA 54/ANSI.

† This length includes an ordinary number of fittings.

Table 3 – Heating Inputs

HEATING INPUT

(BTUH)

NUMBER

GAS SUPPLY PRESSURE (IN. W.C.) MANIFOLD PRESSURE

NUMBER

ORIFICES

Natural{Propane*{

MANIFOLD

PRES

SURE

(IN. W.C.)

ORIFICES

Min Max Min Max Natural{Propane*†

40,000 24.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0

60,000 24.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0

90,000 34.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0

115,000 34.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0

130,000 34.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0

*When a unit is converted to propane, different size orifices must be used. See separate, natural ---to ---propane conversion kit instructions.

{Based on altitudes from sea level to 2000 ft (610 m) above sea level. In th e U.S.A. for altitudes above 2000 ft (610 m), reduce input rating 4 percent for each

additional 1000 ft (305 m) above sea level. In Canada, from 2000 ft (610 m) above sea level to 4500 ft (1372 m) above sea level, derate the unit 10 percent.

48VT--A

4. All units must have field--supplied filters or accessory filter

rack installed in the return--air side of the unit.

Recommended sizes for filters are shown in Table 1.

5. Size all ductwork for maximum required airflow (either

heating or cooling) for unit being installed. Avoid abrupt

duct size increases or decreases or performance may be

affected.

6. Adequately insulate and weatherproof all ductwork located

outdoors. Insulate ducts passing through unconditioned

space, and use vapor barrier in accordance with latest issue

of Sheet Metal and Air Conditioning Contractors National

Association (SMACNA) and Air Conditioning Contractors

of America (ACCA) minimum installation standards for

heating and air conditioning systems. Secure all ducts to

building structure.

7. Flash, weatherproof, and vibration--isolate all openings in

building structure in accordance with local codes and good

building practices.

Step 10 — Install Electrical Connections

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

The unit cabinet must have an uninterrupted, unbroken

electrical ground. This ground may consist of an electrical

wire connected to the unit ground screw in the control

compartment, or conduit approved for electrical ground when

installed in accordance with NEC, NFPA 70 National Fire

Protection Association (latest edition) (in Canada, Canadian

Electrical Code CSA C22.1) and local electrical codes.

!WARNING

UNIT COMPONENT DAMAGE HAZARD

Failure to follow this caution may result in damage to the unit

being installed.

1. Make all electrical connections in accordance with NEC

NFPA 70 (latest edition) and local electrical codes

governing such wiring. In Canada, all electrical

connections must be in accordance with CSA standard

C22.1 Canadian Electrical Code Part 1 and applicable

local codes. Refer to unit wiring diagram.

2. Use only copper conductor for connections between

field--supplied electrical disconnect switch and unit. DO

NOT USE ALUMINUM WIRE.

3. Be sure that high--voltage power to unit is within

operating voltage range indicated on unit rating plate. On

3--phase units, ensure phases are balanced within 2

percent. Consult local power company for correction of

improper voltage and/or phase imbalance.

4. Insulate low--voltage wires for highest voltage contained

within conduit when low--voltage control wires are in

same conduit as high--voltage wires.

5. Do not damage internal components when drilling

through any panel to mount electrical hardware, conduit,

etc.

!CAUTION

High--Voltage Connections

When routing power leads into unit, use only copper wire between

disconnect and unit. The high voltage leads should be in a conduit

until they enter the duct panel; conduit termination at the duct

panel must be watertight.

The unit must have a separate electrical service with a

field--supplied, waterproof disconnect switch mounted at, or within

sight from, the unit. Refer to the unit rating plate, NEC and local

codes for maximum fuse/circuit breaker size and minimum circuit

amps (ampacity) for wire sizing.

The field--supplied disconnect switch box may be mounted on the

unit over the high--voltage inlet hole when the standard power and

low--voltage entry points are used (See Fig. 2 and 3 for acceptable

location).

See unit wiring label (Fig. 15 and 16) and Fig. 10 for reference

when making high voltage connections. Proceed as follows to

complete the high--voltage connections to the unit.

Single phase units:

1. Run the high--voltage (L1, L2) and ground lead into the

control box.

2. Connect ground lead to chassis ground connection.

3. Locate the black and yellow wires connected to the line side

of the contactor.

4. Connect field L1 to black wire on connection 11 of the

compressor contactor.

5.ConnectfieldwireL2toyellowwireonconnection23of

the compressor contactor.

Three--phase units:

1. Run the high--voltage (L1, L2, L3) and ground lead into the

control box.

2. Connect ground lead to chassis ground connection.

3. Locate the black and yellow wires connected to the line side

of the contactor.

4. Connect field L1 to black wire on connection 11 of the

compressor contactor.

5.ConnectfieldwireL3toyellowwireonconnection13of

the compressor contactor.

6. Connect field wire L2 to blue wire from compressor.

Special Procedures for 208--V Operation

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Make surethepower supply to theunit isswitched OFFbefore

making any wiring changes. Tag the disconnect switch with a

suitable warning label. With disconnect switch open, move

black wire from transformer (3/16 in.) terminal marked 230 to

terminal marked 200. This retaps transformer to primary

voltage of 208 vac.

!WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Beforemaking any wiring changes, make sure the gas supply

is switched off first. Then switch off the power supply to the

unit and install lockout tag.

!WARNING

Control Voltage Connections

Do not use any type of power--stealing thermostat. Unit control

problems may result.

Use no. 18 American Wire Gage (AWG) color--coded, insulated

(35_C minimum) wires to make the control voltage connections

between the thermostat and the unit. If the thermostat is located

48VT--A

more than 100 ft (30.5 m) from the unit (as measured along the

control voltage wires), use no. 16 AWG color--coded, insulated

(35_C minimum) wires.

Locate the seven (eight on 3--phase) low voltage thermostat leads

in 24 volt splice box. See Fig. 10 for connection diagram. Run the

low--voltage leads from the thermostat, through the control wiring

inlet hole grommet (Fig. 2 and 3), and into the low--voltage splice

box. Provide a drip loop before running wires through panel.

Secure and strain relief all wires so that they do not interfere with

operation of unit. A gray wire is standard on 3--phase unit for

connection to an economizer.

POWER

SUPPLY

FIELD-SUPPLIED

FUSED DISCONNECT

HIGH VOLTAGE

POWER LEADS

(SEE UNIT WIRING

LABEL)

EQUIP GR

CONTROL BOX

SPLICE BOX

LOW-VOLTAGE

POWER LEADS

(SEE UNIT

WIRING LABEL)

WHT(W1)

YEL(Y)

GRN(G)

RED(R)

BRN(C)

THERMOSTAT

(TYPICAL)

ORN(O)

GRA (Y2)

BLU (DH) DH

3-Phase

Only

A09067

Fig. 10 -- High and Control--Voltage Connections

Balance Point Setting--Thermidistat or Hybrid

Thermostat

BALANCE POINT TEMPERATURE--The “balance point”

temperature is a setting which affects the operation of the heating

mode. This is a field--selected input temperature (range 5 to 55_F)

(--15to12_C) where the Thermidistat or dual fuel thermostat will

monitor outdoor air temperature and decide whether to enable or

disable the heat pump. If the outdoor temperature is above the

“balance point”, the heat pump will energize first to try to satisfy

the indoor temperature demand. If the heat pump does not make a

sufficient improvement within a reasonable time period (i.e. 15

minutes), then the gas furnace will come on to satisfy the indoor

temperature demand. If the outdoor temperature is below the

“balance point”, the heat pump will not be allowed to operate (i.e.

locked out), and the gas furnace will be used to satisfy the indoor

temperature. There are three separate concepts which are related to

selecting the final “balance point” temperature. Read each of the

following carefully to determine the best “balance point” in a

hybrid installation:

1. Capacity Balance Temperature: This is a point where the

heat pump cannot provide sufficient capacity to keep up

with the indoor temperature demand because of declining

outdoor temperature. At or below this point, the furnace is

needed to maintain proper indoor temperature.

2. Economic Balance Temperature: Above this point, the heat

pump is the most cost efficient to operate, and below this

point the furnace is the most cost efficient to operate. This

can be somewhat complicated to determine and it involves

knowing the cost of gas and electricity, as well as the

efficiency of the furnace and heat pump. For the most

economical operation, the heat pump should operate above

this temperature (assuming it has sufficient capacity) and the

furnace should operate below this temperature.

3. Comfort Balance Temperature: When the heat pump is

operating below this point, the indoor supply air feels

uncomfortable (i.e. too cool). This is purely subjective and

will depend on the homeowner’s idea of comfort. Below

this temperature the gas furnace should operate in order to

satisfy the desire for indoor comfort.

Transformer Protection

The transformer is of the energy--limiting type. It is set to withstand

a 30--sec. overload or shorted secondary condition. If an overload

or short is present, correct overload condition and check for blown

fuse on gas control board or Interface Fan Board. Replace fuse as

required with correct size and rating.

PRE--START--UP

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury,

death or property damage.

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 and tagged.

4. Relieve and recover all refrigerant 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 to unit and install lockout

tag.

b. Relieve and reclaim all refrigerant from system

using both high-- and low--pressure ports.

c. Cut component connecting 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.

!WARNING

Proceed as follows to inspect and prepare the unit for initial

start--up:

1. Remove access panels (see Fig. 19).

2. Read and follow instructions on all WARNING,

CAUTION, and INFORMATION labels attached to, or

shipped with, unit.

3. Make the following inspections:

a. Inspect for shipping and handling damages such as

broken lines, loose parts, disconnected wires, etc.

b. Inspect for oil at all refrigerant tubing connections and

on unit base. Detecting oil generally indicates a

refrigerant leak.

c. Leak test all refrigerant tubing connections using

electronic leak detector, halide torch, or liquid--soap

solution. If a refrigerant leak is detected, see the Check

for Refrigerant Leaks section.

d. Inspect all field-- and factory--wiring connections. Be

sure that connections are completed and tight.

48VT--A

e. Ensure wires do not touch refrigerant tubing or sharp

sheet metal edges.

f. Inspect coil fins. If damaged during shipping and

handling, carefully straighten fins with a fin comb.

FIRE, EXPLOSION HAZARD

Failure to follow this warning could result in personal injury,

death or property damage.

Do not purge gas supply into the combustion chamber. Do not

use a match or other open flame to check for gas leaks. Use a

commercially available soap solution made specifically for

the detection of leaks to check all connections.

!WARNING

4. Verify the following conditions:

a. Make sure gas line is free of air. Before lighting the unit

for the first time, perform the following with the gas

valve in the “OFF” position:

NOTE: If the gas supply pipe was not purged before connecting

the unit, it will be full of air. It is recommended that the ground

joint union be loosened, and the supply line be allowed to purge

until the odor of gas is detected. Never purge gas lines into a

combustion chamber. Immediately upon detection of gas odor,

retighten the union. Allow 5 minutes to elapse, then light unit.

b. Make sure that condenser--fan blade is correctly

positioned in fan orifice. Leading edge of condenser--fan

blade should be 1/2 in. (12 mm) maximum from fan

orifice.

c. Make sure that air filter(s) is in place.

d. Make sure that condensate drain trap is filled with water

to ensure proper drainage.

e. Make sure that all tools and miscellaneous loose parts

have been removed.

START--UP

Step 1 — Check for Refrigerant Leaks

Proceed as follows to locate and repair a refrigerant leak and to

charge the unit:

1. Locate leak and make sure that refrigerant system pressure

has been relieved and reclaimed from both high-- and

low--pressure ports.

2. Repair leak following Refrigerant Service procedures.

NOTE: Install a bi--flow filter drier whenever the system has been

opened for repair.

3. Add a small charge of R--410A refrigerant vapor to system

and leak--test unit.

4. Recover refrigerant from refrigerant system and evacuate to

500 microns if no additional leaks are not found.

5. Charge unit with Puron (R--410A) refrigerant, using an

electronic scale. Refer to unit rating plate for required

charge.

Step 2 — Unit Sequence of Operation

48VT--A Sequence of Operation

a. CONTINUOUS FAN

(1.) Thermostat closes circuit R to G energizing the

blower motor for continuous fan.

b. COOLING MODE

(1.) If indoor temperature is above temperature set

point thermostat closes circuits R to G, R to Y and

R to O--The unit delivers cooling airflow.

c. HEAT PUMP HEATING MODE

Outdoor temperature above balance point setpoint of

thermostat.

(1.) On a call for heating, terminals “Y” and “G“ of the

Hybrid thermostat are energized. The “Y“ signal is

sent to the Defrost Board (DB) terminal “Y”. The

DB has a built in five minute anti--short cycle timer

which will not allow the compressor to restart

before the time delay has expired.

(2.) “T2” energizes the compressor contactor via the

High Pressure Switch (HPS) and Low Pressure

Switch (LPS). The compressor and outdoor fan

start. Thermostat “G” energizes the Interface Fan

Board terminal “G”. The blower motor is energized

through contacts of the IFB.

(3.) When the thermostat removes the “Y” and “G”

calls, the compressor contactor and outdoor fan are

de--energized. The evaporator motor is de--ener-

gized after a 90 sec. delay.

d. GAS HEATING MODE

Outdoor temperature below balance point setpoint of

thermostat.

Heating Sequence of Operation

(See Fig. 15 and 16 and unit wiring label.)

On a call for heating, terminal W of the thermostat is energized,

starting the induced--draft motor. When the pressure switch senses

that the induced--draft motor is moving sufficient combustion air,

the burner sequence begins. This function is performed by the

integrated gas unit controller (IGC). The indoor (evaporator)--fan

motor is energized 45 sec after flame is established. When the

thermostat is satisfied and W is de--energized, the burners stop

firing and the indoor (evaporator) fan motor shuts off after a

45--sec time--off delay. Please note that the IGC has the capability

to automatically reduce the indoor fan motor on delay and increase

the indoor fan motor off delay in the event of high duct static

and/or partially--clogged filter.

NOTE: An LED (light--emitting diode) indicator is provided on

the control board to monitor operation. The control board is

located by removing the burner access panel (see Fig. 19). During

normal operation, the LED is continuously on.

Step 3 — Start--up Heating and Make Adjust-

ments

UNIT COMPONENT DAMAGE HAZARD

Failure to follow this caution may result in damage to the unit

being installed.

Complete the required procedures given in the Pre--Start--Up

section before starting the unit. Do not jumper any safety

devices when operating the unit.

!CAUTION

Complete the required procedures given in the Pre--Start--Up

section before starting the unit. Do not jumper any safety devices

when operating the unit. Make sure that burner orifices are

properly aligned. Unstable operation my occur when the burner

orifices in the manifold are misaligned.

Follow the lighting instructions on the heating section operation

label (located on the inside of the control access panel) to start the

heating section.

NOTE: Make sure that gas supply has been purged, and that all

gas piping has been checked for leaks.

48VT--A

Pipe Plug Manifold

A07679

Fig. 11 -- Burner Assembly

MANIFOLD

BURNER

BURNER FLAME

C99021

Fig. 12 -- Monoport Burner

Check Heating Control

Start and check the unit for proper heating control operation as

follows (see furnace lighting instructions located on the inside of

the control access panel):

1. Place room thermostat SYSTEM switch in the HEAT

position and the fan switch is placed in AUTO position.

2. Set the heating temperature control of the thermostat above

room temperature.

3. The induced--draft motor will start.

4. On a call for heating, the main burner should light within 5

sec. of the spark being energized. If the burners do not light,

there is a 22--sec. delay before another 5--sec. try. If the

burners still do not light, this sequence is repeated. If the

burners do not light within 15 minutes from the initial call

for heat, there is a lockout. To reset the control, break the

24--v power to W.

5. The evaporator fan will turn on 45 sec. after the flame has

been established. The evaporator fan will turn off 45 sec.

after the thermostat has been satisfied. Please note that the

integrated gas unit controller (IGC) has the capability to

automatically reduce the evaporator “ON” delay and in-

crease the evaporator “OFF” delay in the event of high duct

static and/or partially--clogged filter.

Check Gas Input

Check gas input and manifold pressure after unit start--up (See

Table 3). If adjustment is required proceed as follows:

SThe rated gas inputs shown in Table 3 are for altitudes from sea

level to 2000 ft (610 m) above sea level. These inputs are based

on natural gas with a heating value of 1025 Btu/ft3at 0.60

specific gravity, or propane gas with a heating value of 2500

Btu/ft3at 1.5 specific gravity.

IN THE U.S.A.:

The input rating for altitudes above 2,000 ft (610 m) must be

reduced by 4% for each 1,000 ft (305 m) above see level.

For installations below 2,000 ft (610 m), refer to the unit rating

plate.

For installations above 2,000 ft (610 m) multiply the input by on

the rating plate by the derate multiplier in Table 4 for correct input

rate.

Table 4 – Altitude Derate Multiplier for U.S.A.*

ALTITUDE FT (M) PERCENT OF DERATE DERATE MULTIPLIER

FACTOR{

0--- 2000

(0--- 610) 01.00

2001--- 3000*

(610--- 914) 8 --- 1 2 0.90

3001--- 4000

(315--- 1219) 12--- 16 0.86

4001--- 5000

(1220--- 1524) 16--- 20 0.82

5001--- 6000

(1524--- 1829) 20--- 24 0.78

6001--- 7000

(1829--- 2134) 24--- 28 0.74

7001--- 8000

(2134--- 2438) 28--- 32 0.70

8001--- 9000

(2439--- 2743) 32--- 36 0.66

9001--- 10,000

(2744--- 3048) 36--- 40 0.62

* In Canada see Canadian Altitude Adjustment.

{Derate multiplier factors are based on midpoint altitude for altitude range.

IN CANADA:

The input rating for altitudes from 2,000 to 4,500 ft (610 m to

1372 m) above sea level must be derated 10% by an authorized

Gas Conversion Station or Dealer.

EXAMPLE:

90,000 Btu/hr Input Furnace Installed at 4300 ft (1311 m).

Furnace Input Rate at

Sea Level

XDerateMultiplier

Factor

= Furnace Input Rate at

Installation Altitude

90,000 X 0.90 = 81,000

When the gas supply being used has a different heating value or

specific gravity, refer to national and local codes, or contact your

distributor to determine the required orifice size.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in reduced unit

and/or component life.

Do Not redrill an orifice. Improper drilling (burrs,

out--of--round holes, etc.) can cause excessive burner noise

and misdirection of burner flame. If orifice hole appears

damaged or it is suspected to have been redrilled, check

orifice hole with a numbered drill bit of correct size.

!CAUTION

Adjust Gas Input

The gas input to the unit is determined by measuring the gas flow

at the meter or by measuring the manifold pressure. Measuring the

gas flow at the meter is recommended for natural gas units. The

manifold pressure must be measured to determine the input of

propane gas units.

Measure Gas Flow (Natural Gas Units)

Minor adjustment to the gas flow can be made by changing the

manifold pressure. The manifold pressure must be maintained

between 3.2 and 3.8 IN. W.C.

48VT--A

REGULATOR

COVER SCREW

ADJUSTMENT

SCREW

REGULATOR SPRING

(PROPANE - WHITE)

NATURAL - SILVER)

GAS PRESSURE

REGULATOR

ADJUSTMENT

MANIFOLD

PRESSURE TAP

INLET

PRESSURE TAP

ON/OFF SWITCH

PLASTIC

(

A07751

Fig. 13 -- Single--Stage Gas Valve

If larger adjustments are required, change main burner orifices

following the recommendations of national and local codes.

NOTE: All other appliances that use the same meter must be

turned off when gas flow is measured at the meter.

Proceed as follows:

1. Turn off gas supply to unit.

2. Remove pipe plug on manifold (See Fig. 11) and connect

manometer. Turn on gas supply to unit.

3. Record number of seconds for gas meter test dial to make

one revolution.

4. Divide number of seconds in Step 3 into 3600 (number of

seconds in one hr).

5. Multiply result of Step 4 by the number of cubic feet (cu ft)

shown for one revolution of test dial to obtain cubic feet (cu

ft) of gas flow per hour.

6. Multiply result of Step 5 by Btu heating value of gas to

obtain total measured input in Btuh. Compare this value

with heating input shown in Table 3 (Consult the local gas

supplier if the heating value of gas is not known).

EXAMPLE: Assume that the size of test dial is 1 cu ft, one

revolution takes 32 sec, and the heating value of the gas is 1050

Btu/ft3. Proceed as follows:

1. 32 sec. to complete one revolution.

2. 3600 ÷32 = 112.5.

3. 112.5x1=112.5ft

3of gas flow/hr.

4. 112.5 x 1050 = 118,125 Btuh input.

If the desired gas input is 115,000 Btuh, only a minor change in the

manifold pressure is required.

Observe manifold pressure and proceed as follows to adjust gas

input:

1. Remove regulator cover screw over plastic adjustment

screw on gas valve (See Fig. 13).

2. Turn plastic adjustment screw clockwise to increase gas

input, or turn plastic adjustment screw counterclockwise to

decrease input (See Fig. 13). Manifold pressure must be

between 3.2 and 3.8 IN. W.C.

FIRE AND UNIT DAMAGE HAZARD

Failure to follow this warning could result in personal

injury or death and/or property damage.

Unsafe operation of the unit may result if manifold pressure

is outside this range.

!WARNING

3. Replace regulator cover screw on gas valve (See Fig. 13).

4. Turn off gas supply to unit. Remove manometer from

pressure tap and replace pipe plug on gas valve. (See Fig.

11.) Turn on gas to unit and check for leaks.

Measure Manifold Pressure (Propane Units)

Refer to propane kit installation instructions for properly checking

gas input.

NOTE: For installations below 2,000 ft (610 m), refer to the unit

rating plate for proper propane conversion kit. For installations

above 2,000 ft (610 m), contact your distributor for proper propane

conversion kit.

Check Burner Flame

With control access panel (see Fig. 19) removed, observe the unit

heating operation. Watch the burner flames to see if they are light

blue and soft in appearance, and that the flames are approximately

the same for each burner. Propane will have blue flame (See Fig.

12). Refer to the Maintenance section for information on burner

removal.

Normal Operation

An LED (light--emitting diode) indicator is provided on the

integrated gas unit controller (IGC) to monitor operation. The IGC

is located by removing the control access panel (see Fig. 19).

During normal operation, the LED is continuously on (See Table 5

for error codes).

Airflow and Temperature Rise

The heating section for each size unit is designed and approved for

heating operation within the temperature--rise range stamped on the

unit rating plate.

Table 10 shows the approved temperature rise range for each

heating input, and the air delivery cfm at various temperature rises

for a given external static pressure. The heating operation airflow

must produce a temperature rise that falls within the approved

range.

Refer to Indoor Airflow and Airflow Adjustments section to adjust

heating airflow when required.

Limit Switches

Normally closed limit switch (LS) completes the control circuit.

Should the leaving--air temperature rise above the maximum

allowable temperature, the limit switch opens and the control

circuit “breaks.” Any interruption in the control circuit instantly

closes the gas valve and stops gas flow to the burners and pilot.

The blower motor continues to run until LS resets.

When the air temperature at the limit switch drops to the

low--temperature setting of the limit switch, the switch closes and

48VT--A

completes the control circuit. The direct--spark ignition system

cycles and the unit returns to normal heating operation.

Table 5 – LED Indications

STATUS CODE LED INDICATION

Normal Operation2On

No Power Hardware Failure Off

Limit Switch Fault 2 Flashes

Flame Sense Fault 3 Flashes

Four Consecutive Limit Switch Faults 4 Flashes

Ignition Lockout Fault 5 Flashes

Pressure Switch Fault 6 Flashes

Rollout Switch Fault 7 Flashes

Internal Control Fault 8 Flashes

Temporary 1 hr auto reset19 Flashes

NOTES:

1.This code indicates an internal processor fault that will reset itself in one

hr. Fault can be caused by stray RF signals in the structure or nearby. This

is a UL requirement.

2. LED indicates acceptable operation. Do not change ignition control

board.

3. When W is energized the burners will remain on for a minimum of 60 sec.

4.IfmorethanoneerrormodeexiststheywillbedisplayedontheLEDin

sequence.

Rollout Switch

The function of the rollout switch is to close the main gas valve in

the event of flame rollout. The switch is located above the main

burners. When the temperature at the rollout switch reaches the

maximum allowable temperature, the control circuit trips, closing

the gas valve and stopping gas flow to the burners. The indoor

(evaporator) fan motor (IFM) and induced draft motor continue to

run until switch is reset. The IGC LED will display FAULT CODE

Step 4 — Start--up Cooling and Make Adjust-

ments

Complete the required procedures given in the Pre--Start--Up

section before starting the unit. Do not jumper any safety devices

when operating the unit. Do not operate the compressor when the

outdoor temperature is below 40°F(4.4°C) (unless accessory

low--ambient kit is installed). Do not rapid--cycle the compressor.

Allow 5 minutes between on cycles to prevent compressor damage.

Checking Cooling Control Operation

Start and check the unit for proper cooling control operation as

follows:

1. Place room thermostat SYSTEM switch in OFF position.

Observe that blower motor starts when FAN switch is

placed in ON position and shuts down when FAN switch is

placed in AUTO position.

2. Place SYSTEM switch in COOL position and FAN switch

in AUTO position. Set cooling control below room

temperature. Observe that compressor, condenser fan, and

evaporator blower motors start. Observe that cooling cycle

shuts down when control setting is satisfied. The evaporator

fan will continue to run for 90 sec.

IMPORTANT: Three--phase, scroll compressors units are

direction oriented. Unit must be checked to ensure proper

compressor 3--phase power lead orientation. If not corrected within

5 minutes, the internal protector will shut off the compressor. The

3--phase power leads to the unit must be reversed to correct

rotation. When turning backwards, the difference between

compressor suction and discharge pressures will be near zero.

Checking and Adjusting Refrigerant Charge

The refrigerant system is fully charged with PuronR(R--410A)

refrigerant and is tested and factory sealed. Allow system to operate

a minimum of 15 minutes before checking or adjusting charge.

NOTE: Adjustment of the refrigerant charge is not required unless

the unit is suspected of not having the proper PuronR(R--410A)

charge.

The charging label and the tables shown refer to system

temperatures and pressures in cooling mode only. A refrigerant

charging label is attached to the inside of the compressor access

panel (see Fig. 19). The chart includes the required liquid line

temperature at given discharge line pressures and outdoor ambient

temperatures.

An accurate thermocouple-- or thermistor--type thermometer, and a

gauge manifold are required when using the subcooling charging

method for evaluating the unit charge. Do not use mercury or small

dial--type thermometers because they are not adequate for this type

of measurement.

UNIT DAMAGE HAZARD

Failure to follow this caution may result in unit damage.

When evaluating the refrigerant charge, an indicated

adjustment to the specified factory charge must always be

very minimal. If a substantial adjustment is indicated, an

abnormal condition exists somewhere in the cooling system,

such as insufficient airflow across either coil or both coils.

!CAUTION

Proceed as follows:

1. Remove caps from low-- and high--pressure service fittings.

2. Using hoses with valve core depressors, attach low-- and

high--pressure gauge hoses to low-- and high--pressure

service fittings, respectively.

3. Start unit in Cooling Mode and let unit run until system

pressures stabilize.

4. Measure and record the following:

a. Outdoor ambient--air temperature (°F(°C) db).

b. Liquid line temperature (°F(°C).

c. Discharge (high--side) pressure (psig).

d. Suction (low--side) pressure (psig) (for reference only).

5. Using “Cooling Charging Charts,” compare outdoor--air

temperature(°F(°C) db) with the discharge line pressure

(psig) to determine desired system operating liquid line

temperature (See Fig. 17).

6. Compare actual liquid line temperature with desired liquid

line temperature. Using a tolerance of ±2°F(±1.1°C), add

refrigerant if actual temperature is more than 2°F(1.1°C)

higher than proper liquid line temperature, or remove

refrigerant if actual temperature is more than 2°F(1.1°C)

lower than required liquid line temperature.

NOTE: If the problem causing the inaccurate readings is a

refrigerant leak, refer to the Check for Refrigerant Leaks section.

Indoor Airflow and Airflow Adjustments

UNIT OPERATION HAZARD

Failure to follow this caution may result in unit damage.

For cooling operation, the recommended airflow is 350 to

450 cfm for each 12,000 Btuh of rated cooling capacity. For

heating operation, the airflow must produce a temperature

rise that falls within the range stamped on the unit rating

plate.

CAUTION

NOTE: Be sure that all supply--and return--air grilles are open,

free from obstructions, and adjusted properly.

48VT--A

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal

injury or death.

Before making any indoor wiring adjustments, shut off gas

supply. Then disconnect electrical power to the unit and

install lockout tag before changing blower speed.

!WARNING

This unit has independent fan speeds for gas heating and cooling.

In addition, this unit has the field-selectable capability to run two

different cooling fan speeds: A normal cooling fan speed (350~400

CFM/Ton) and an enhanced dehumidification fan speed (As low as

320 CFM/Ton) for use with either a dehumidistat or a thermostat

that supports dehumidification.

This unit is factory-set up for use with a single cooling fan speed.

The cooling speed is marked “LOW” on the interface fan board

(IFB) (Fig. 14) . The factory-shipped settings are noted in Table

10. There are 3 additional speed tap wires available for use in

either gas heating or cooling (For color coding on the indoor fan

motor leads, see Table 6). The additional 3 speed tap wires are

shipped loose with vinyl caps and are located in the control box,

near the interface fan board (IFB) (Fig. 14).

Gas Heating Fan Speed Set-up

To change the gas heating speed:

1. Remove the vinyl cap off of the desired speed tap wire

(Refer to Table 6 for color coding). Table 10 shows the

temperature rise associated with each fan speed for a given

static pressure. Make sure that the speed chosen delivers a

temperature rise within the rise range listed on the unit

rating plate.

2. Remove the current speed tap wire from the “GAS HEAT”

terminal on the interface fan board (IFB) (Fig.14) and place

vinyl cap over the connector on the wire.

3. Connect the desired speed tap wire to the “GAS HEAT”

terminal on the interface fan board (IFB).

Single Cooling Fan Speed Set-up (Dehumidification

feature not used)

To change cooling speed:

1. Remove the vinyl cap off of the desired speed tap wire

(Refer to Table 6 for color coding). Add the wet coil

pressure drop in Table 8 to the system static to determine the

correct cooling airflow speed in Table 10 that will deliver

the nominal cooling airflow as listed in Table 1 for each

size.

2. Remove the current speed tap wire from the “LOW”

terminal on the interface fan board (IFB) (Fig. 14) and place

vinyl cap over the connector on the wire.

3. Connect the desired speed tap wire to the “LOW” terminal

on the interface fan board (IFB).

Two Cooling Fan Speeds Set-up (Dehumidification

feature used)

IMPORTANT: Dehumidification control must open control

circuit on humidity rise above set point.

Use of the dehumidification cooling fan speed requires use of

either a 24 VAC dehumidistat or a thermostat which includes

control of a 24 VAC dehumidistat connection. In either case, the

dehumidification control must open the control circuit on humidity

rise above the dehumidification set point. Dehumidification

controls are available with the reverse logic; these must not be

used.

1. Remove fan speed tap wire from the “LOW” terminal on

the interface fan board (IFB) (Fig. 14).

2. Determine correct normal cooling fan speed for unit and

application. Add the wet coil pressure drop in Table 8 to

the system static to determine the correct cooling airflow

speed in Table 10 that will deliver the nominal cooling

airflow as listed in Table 1 for each size.

3. Remove the vinyl cap off of the desired speed tap wire

(Refer to Table 6 for color coding) for the normal cooling

fan speed and place desired speed tap wire on “HIGH” on

the interface board.

4. Refer to airflow tables (Table 10) to determine allowable

speeds for the dehumidification cooling fan speed. In Table

10, speeds that are not allowed for dehumidification cooling

are shaded.

5. Remove the vinyl cap off of the desired speed tap wire

(Refer to Table 6 for color coding) for the dehumidification

cooling fan speed and place desired speed tap wire on the

“LOW” connection on the interface board (IFB). Verify

that static pressure is in the acceptable range for the speed

tap to be used for dehumidification cooling.

6. Use any spare vinyl plugs to cap any unused speed tap

wires.

NOTE: For heat pump operation, the recommended airflow is 350

to 450 CFM for each 12,000 Btuh of rated cooling capacity.

Continuous Fan Operation

When the DEHUM feature is not used, the continuous fan speed

will be the same as cooling fan speed. When the DEHUM feature

is used, the continuous fan will operate on IFB “LOW” speed

when the DH control lead is not energized, or IFB “HIGH” speed

when the DH lead is energized (see Fig. 14).

Table 6 – Color Coding for Indoor Fan Motor Leads

Black = High Speed

Orange = Med---High Speed

Red=MedSpeed

P i n k = M e d --- L o w S p e e d

Blue = Low Speed

48VT--A

COMLOWHIGH

GAS

HEAT

Q1R1LC8RL3

DCR QCR

QC1

D4D6C2OILL

R9 AB A15

R4 RL4

R2 R3 R5 R6

QCB

YY R U C 24VAC

JW1

W2 Y2/ Y1/

YDH GCR

SSTZ-8

P3 SDL

24VAC/R CDM/C

QC6 QC7 QC4 QC3

K2 K1

RI0

RI2

JM6

RI DL

JM5

D3D5

JW3

JW2

JW4

JW7

3 AMP

A09058

Fig. 14 -- Interface Fan Board (IFB)

Table 7 – Filter Pressure Drop Table (IN. W.C.)

FILTER SIZE

in. (mm)

CFM

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300

20X20X1

(508X508X25) 0.05 0.07 0.08 0.1 0.12 0.13 0.14 0.15 ———————————

20X24X1

(508X610x25 ) — — — — 0.09 0.10 0.11 0.13 0.14 0.15 0.16 — — — — — — — —

24X30X1

(610X762x25) — — — 0.04 0.05 0.06 0.07 0.07 0.08 0.09 0.1 — — — — — — — —

24X36X1

(610X914X25) — — — — — — — 0.06 0.07 0.07 0.08 0.09 0.09 0.10 0.11 0.12 0.13 0.14 0.14

Table 8 – 48VT--A Wet Coil Pressure Drop

Unit Size Standard CFM (S.C.F.M)

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

24 0.06 0.07 0.08 0.09 0.1

30 0.12 0.15 0.19 0.23 0.27

36 0.07 0.11 0.18 0.26 0.35

42 0.04 0.07 0.1 0.15 0.21

48 0.11 0.14 0.17 0.22 0.28

60 0.1 0.17 0.23 0.31 0.36

Table 9 – Wet Coil Air Delivery - Downflow -- High Speed with 1--in. Filter and Economizer

UNIT SIZE EXTERNAL STATIC PRESSURE (in. W.C.)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

36, 42 1612 1569 1527 1481 1451 1393 1351 1317 1278 1242

48 2298 2239 2180 2110 2044 1951 1862 1777 1697 1591

60 2000 1926 1825 1820 1759 1705 1634 1496 1412 1328

48VT--A

Table 10 – Dry Coil Air Delivery* -- Horizontal and Downflow Discharge -- Unit 48VT--A24--60

UNIT

HEATING

RISE

RANGE

MOTOR

SPEED

WIRE

COLOR

EXTERNAL STATIC PRESSURE (in. W.C.)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

48VT(-,N)A24040 30 - 60oF

(17 - 33oC)

Low Blue

CFM 741 638 547 415 --- --- --- --- ---

Heating

Rise (oF) 41 47 55 NA NA NA NA NA NA

Heating

Rise (oC) 23 26 31 NA NA NA NA NA NA

Med-Low2Pink

CFM 898 820 738 662 536 --- --- --- ---

Heating

Rise (oF) 34 37 41 46 56 NA NA NA NA

Heating

Rise (oC) 19 20 23 25 31 NA NA NA NA

Medium1Red

CFM 973 887 823 733 665 538 451 --- ---

Heating

Rise (oF) 31 34 37 41 45 56 NA NA NA

Heating

Rise (oC) 17 19 20 23 25 31 NA NA NA

Med-High Orange

CFM 1140 1064 996 915 840 758 687 564 480

Heating

Rise (oF) NA NA 30 33 36 40 44 54 NA

Heating

Rise (oC) NA NA 17 18 20 22 24 30 NA

High Black

CFM 1202 1140 1082 1015 961 881 810 732 631

Heating

Rise (oF) NA NA NA 30 31 34 37 41 48

Heating

Rise (oC) NA NA NA 17 17 19 21 23 27

48VT(-,N)A24060 25 - 55oF

(14 - 31oC)

Low Blue

CFM 741 638 547 415 --- --- --- --- ---

Heating

Rise (oF) NA NA NA NA NA NA NA NA NA

Heating

Rise (oC) NA NA NA NA NA NA NA NA NA

Med-Low2Pink

CFM 898 820 738 662 536 --- --- --- ---

Heating

Rise (oF) 49 54 NA NA NA NA NA NA NA

Heating

Rise (oC) 27 30 NA NA NA NA NA NA NA

Medium Red

CFM 973 887 823 733 665 538 451 --- ---

Heating

Rise (oF) 46 50 54 NA NA NA NA NA NA

Heating

Rise (oC) 25 28 30 NA NA NA NA NA NA

Med-High Orange

CFM 1140 1064 996 915 840 758 687 564 480

Heating

Rise (oF) 39 42 45 49 53 NA NA NA NA

Heating

Rise (oC) 22 23 25 27 29 NA NA NA NA

High1Black

CFM 1202 1140 1082 1015 961 881 810 732 631

Heating

Rise (oF) 37 39 41 44 46 50 55 NA NA

Heating

Rise (oC) 21 22 23 24 26 28 30 NA NA

48VT(-,N)A30040 30 - 60oF

(17 - 33oC)

Low Blue

CFM 741 638 547 415 --- --- --- --- ---

Heating

Rise (oF) 41 47 55 NA NA NA NA NA NA

Heating

Rise (oC) 23 26 31 NA NA NA NA NA NA

Med-Low Pink

CFM 898 820 738 662 536 --- --- --- ---

Heating

Rise (oF) 34 37 41 46 56 NA NA NA NA

Heating

Rise (oC) 19 20 23 25 31 NA NA NA NA

Medium1Red

CFM 973 887 823 733 665 538 451 --- ---

Heating

Rise (oF) 31 34 37 41 45 56 NA NA NA

Heating

Rise (oC) 17 19 20 23 25 31 NA NA NA

Med-High2Orange

CFM 1140 1064 996 915 840 758 687 564 480

Heating

Rise (oF) NA NA 30 33 36 40 44 54 NA

Heating

Rise (oC) NA NA 17 18 20 22 24 30 NA

High Black

CFM 1202 1140 1082 1015 961 881 810 732 631

Heating

Rise (oF) NA NA NA 30 31 34 37 41 48

Heating

Rise (oC) NA NA NA 17 17 19 21 23 27

48VT--A

Table 10 -- Dry Coil Air Delivery* -- Horizontal and Downflow Discharge -- Unit 48VT--A24--60 Cont

UNIT

HEATING

RISE

RANGE

MOTOR

SPEED

WIRE

COLOR

EXTERNAL STATIC PRESSURE (in. W.C.)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

48VT(-,N)A30060 25 - 55oF

(14 - 31oC)

Low Blue

CFM 741 638 547 415 --- --- --- --- ---

Heating

Rise (oF) NA NA NA NA NA NA NA NA NA

Heating

Rise (oC) NA NA NA NA NA NA NA NA NA

Med-Low Pink

CFM 898 820 738 662 536 --- --- --- ---

Heating

Rise (oF) 49 54 NA NA NA NA NA NA NA

Heating

Rise (oC) 27 30 NA NA NA NA NA NA NA

Medium Red

CFM 973 887 823 733 665 538 451 --- ---

Heating

Rise (oF) 46 50 54 NA NA NA NA NA NA

Heating

Rise (oC) 25 28 30 NA NA NA NA NA NA

Med-High2Orange

CFM 1140 1064 996 915 840 758 687 564 480

Heating

Rise (oF) 39 42 45 49 53 NA NA NA NA

Heating

Rise (oC) 22 23 25 27 29 NA NA NA NA

High1Black

CFM 1202 1140 1082 1015 961 881 810 732 631

Heating

Rise (oF) 37 39 41 44 46 50 55 NA NA

Heating

Rise (oC) 21 22 23 24 26 28 30 NA NA

48VT(-,N)A36060 25 - 55oF

(14 - 31oC)

Low1Blue

CFM 1295 1234 1182 1126 1075 1016 955 898 857

Heating

Rise (oF) 34 36 38 39 41 44 47 49 52

Heating

Rise (oC) 19 20 21 22 23 24 26 27 29

Med-Low Pink

CFM 1345 1282 1235 1194 1140 1095 1027 974 921

Heating

Rise (oF) 33 35 36 37 39 41 43 46 48

Heating

Rise (oC) 18 19 20 21 22 23 24 25 27

Medium Red

CFM 1505 1452 1413 1358 1323 1282 1234 1169 1130

Heating

Rise (oF) 30 31 31 33 34 35 36 38 39

Heating

Rise (oC) 16 17 17 18 19 19 20 21 22

Med-High2Orange

CFM 1545 1492 1449 1411 1362 1313 1278 1231 1188

Heating

Rise (oF) 29 30 31 31 33 34 35 36 37

Heating

Rise (oC) 16 17 17 17 18 19 19 20 21

High Black

CFM 1705 1643 1607 1568 1518 1483 1448 1404 1360

Heating

Rise (oF) 26 27 28 28 29 30 31 32 33

Heating

Rise (oC) 14 15 15 16 16 17 17 18 18

48VT(-,N)A36090 35 - 65oF

(19 - 36oC)

Low Blue

CFM 1295 1234 1182 1126 1075 1016 955 898 857

Heating

Rise (oF) 53 55 58 60 63 NA NA NA NA

Heating

Rise (oC) 29 31 32 34 35 NA NA NA NA

Med-Low Pink

CFM 1345 1282 1235 1194 1140 1095 1027 974 921

Heating

Rise (oF) 51 53 55 57 60 62 NA NA NA

Heating

Rise (oC) 28 29 31 32 33 35 NA NA NA

Medium1Red

CFM 1505 1452 1413 1358 1323 1282 1234 1169 1130

Heating

Rise (oF) 45 47 48 50 51 53 55 58 60

Heating

Rise (oC) 25 26 27 28 29 29 31 32 33

Med-High2Orange

CFM 1545 1492 1449 1411 1362 1313 1278 1231 1188

Heating

Rise (oF) 44 46 47 48 50 52 53 55 57

Heating

Rise (oC) 24 25 26 27 28 29 30 31 32

High Black

CFM 1705 1643 1607 1568 1518 1483 1448 1404 1360

Heating

Rise (oF) 40 41 42 43 45 46 47 48 50

Heating

Rise (oC) 22 23 24 24 25 25 26 27 28

48VT--A

Table 10 -- Dry Coil Air Delivery* -- Horizontal and Downflow Discharge -- Unit 48VT--A24--60 Cont

UNIT

HEATING

RISE

RANGE

MOTOR

SPEED

WIRE

COLOR

EXTERNAL STATIC PRESSURE (in. W.C.)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

48VT(-,N)A42060 25 - 55oF

(14 - 31oC)

Low1Blue

CFM 1295 1234 1182 1126 1075 1016 955 898 857

Heating

Rise (oF) 34 36 38 39 41 44 47 49 52

Heating

Rise (oC) 19 20 21 22 23 24 26 27 29

Med-Low Pink

CFM 1345 1282 1235 1194 1140 1095 1027 974 921

Heating

Rise (oF) 33 35 36 37 39 41 43 46 48

Heating

Rise (oC) 18 19 20 21 22 23 24 25 27

Medium Red

CFM 1505 1452 1413 1358 1323 1282 1234 1169 1130

Heating

Rise (oF) 30 31 31 33 34 35 36 38 39

Heating

Rise (oC) 16 17 17 18 19 19 20 21 22

Med-High2Orange

CFM 1545 1492 1449 1411 1362 1313 1278 1231 1188

Heating

Rise (oF) 29 30 31 31 33 34 35 36 37

Heating

Rise (oC) 16 17 17 17 18 19 19 20 21

High Black

CFM 1705 1643 1607 1568 1518 1483 1448 1404 1360

Heating

Rise (oF) 26 27 28 28 29 30 31 32 33

Heating

Rise (oC) 14 15 15 16 16 17 17 18 18

48VT(-,N)A42090 35 - 65oF

(19 - 36oC)

Low Blue

CFM 1295 1234 1182 1126 1075 1016 955 898 857

Heating

Rise (oF) 53 55 58 60 63 NA NA NA NA

Heating

Rise (oC) 29 31 32 34 35 NA NA NA NA

Med-Low Pink

CFM 1345 1282 1235 1194 1140 1095 1027 974 921

Heating

Rise (oF) 51 53 55 57 60 62 NA NA NA

Heating

Rise (oC) 28 29 31 32 33 35 NA NA NA

Medium1Red

CFM 1505 1452 1413 1358 1323 1282 1234 1169 1130

Heating

Rise (oF) 45 47 48 50 51 53 55 58 60

Heating

Rise (oC) 25 26 27 28 29 29 31 32 33

Med-High2Orange

CFM 1545 1492 1449 1411 1362 1313 1278 1231 1188

Heating

Rise (oF) 44 46 47 48 50 52 53 55 57

Heating

Rise (oC) 24 25 26 27 28 29 30 31 32

High Black

CFM 1705 1643 1607 1568 1518 1483 1448 1404 1360

Heating

Rise (oF) 40 41 42 43 45 46 47 48 50

Heating

Rise (oC) 22 23 24 24 25 25 26 27 28

48VT(-,N)A48090 35 - 65oF

(19 - 36oC)

Low1Blue

CFM 1445 1389 1341 1281 1236 1189 1139 1072 1027

Heating

Rise (oF) 47 49 51 53 55 57 60 63 NA

Heating

Rise (oC) 26 27 28 29 31 32 33 35 NA

Med-Low2Pink

CFM 1678 1635 1602 1558 1513 1474 1438 1404 1349

Heating

Rise (oF) 41 42 42 44 45 46 47 48 50

Heating

Rise (oC) 23 23 24 24 25 26 26 27 28

Medium Red

CFM 1962 1915 1880 1843 1794 1753 1711 1675 1628

Heating

Rise (oF) 35 36 36 37 38 39 40 41 42

Heating

Rise (oC) 19 20 20 20 21 22 22 23 23

Med-High Orange

CFM 2131 2088 2065 2013 1982 1941 1888 1860 1785

Heating

Rise (oF) NA NA NA NA NA 35 36 37 38

Heating

Rise (oC) NA NA NA NA NA 19 20 20 21

High Black

CFM 2461 2409 2339 2286 2192 2140 2062 1968 1874

Heating

Rise (oF) NA NA NA NA NA NA NA 35 36

Heating

Rise (oC) NA NA NA NA NA NA NA 19 20

48VT--A

Table 10 -- Dry Coil Air Delivery* -- Horizontal and Downflow Discharge -- Unit 48VT--A24--60 Cont

UNIT

HEATING

RISE

RANGE

MOTOR

SPEED

WIRE

COLOR

EXTERNAL STATIC PRESSURE (in. W.C.)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

48VT(-,N)A48115 30 - 60oF

(17 - 33oC)

Low Blue

CFM 1445 1389 1341 1281 1236 1189 1139 1072 1027

Heating

Rise (oF) 60 NA NA NA NA NA NA NA NA

Heating

Rise (oC) 33 NA NA NA NA NA NA NA NA

Med-Low2Pink

CFM 1678 1635 1602 1558 1513 1474 1438 1404 1349

Heating

Rise (oF) 52 53 54 56 57 59 60 NA NA

Heating

Rise (oC) 29 30 30 31 32 33 34 NA NA

Medium Red

CFM 1962 1915 1880 1843 1794 1753 1711 1675 1628

Heating

Rise (oF) 44 45 46 47 48 50 51 52 53

Heating

Rise (oC) 25 25 26 26 27 28 28 29 30

Med-High1Orange

CFM 2131 2088 2065 2013 1982 1941 1888 1860 1785

Heating

Rise (oF) 41 42 42 43 44 45 46 47 49

Heating

Rise (oC) 23 23 23 24 24 25 26 26 27

High Black

CFM 2461 2409 2339 2286 2192 2140 2062 1968 1874

Heating

Rise (oF) 35 36 37 38 40 41 42 44 46

Heating

Rise (oC) 20 20 21 21 22 23 23 25 26

48VT(-,N)A48130 35 - 65oF

(19 - 36oC)

Low Blue

CFM 1445 1389 1341 1281 1236 1189 1139 1072 1027

Heating

Rise (oF) NA NA NA NA NA NA NA NA NA

Heating

Rise (oC) NA NA NA NA NA NA NA NA NA

Med-Low2Pink

CFM 1678 1635 1602 1558 1513 1474 1438 1404 1349

Heating

Rise (oF) 57 59 60 62 64 65 NA NA NA

Heating

Rise (oC) 32 33 33 34 35 36 NA NA NA

Medium Red

CFM 1962 1915 1880 1843 1794 1753 1711 1675 1628

Heating

Rise (oF) 49 50 51 52 54 55 56 57 59

Heating

Rise (oC) 27 28 28 29 30 31 31 32 33

Med-High1Orange

CFM 2131 2088 2065 2013 1982 1941 1888 1860 1785

Heating

Rise (oF) 45 46 47 48 49 50 51 52 54

Heating

Rise (oC) 25 26 26 27 27 28 28 29 30

High Black

CFM 2461 2409 2339 2286 2192 2140 2062 1968 1874

Heating

Rise (oF) 39 40 41 42 44 45 47 49 51

Heating

Rise (oC) 22 22 23 23 24 25 26 27 29

48VT(-,N)A60090 35 - 65oF

(19 - 36oC)

Low1Blue

CFM 1448 1362 1296 1226 1168 1108 1071 998 905

Heating

Rise (oF) 47 50 52 55 58 61 63 NA NA

Heating

Rise (oC) 26 28 29 31 32 34 35 NA NA

Med-Low Pink

CFM 1722 1675 1614 1543 1499 1442 1408 1356 1308

Heating

Rise (oF) 39 41 42 44 45 47 48 50 52

Heating

Rise (oC) 22 23 23 24 25 26 27 28 29

Medium2Red

CFM 1887 1847 1783 1726 1677 1625 1578 1527 1432

Heating

Rise (oF) 36 37 38 39 41 42 43 45 47

Heating

Rise (oC) 20 20 21 22 23 23 24 25 26

Med-High Orange

CFM 2055 2008 1958 1927 1900 1768 1685 1581 1458

Heating

Rise (oF) NA NA 35 35 36 38 40 43 47

Heating

Rise (oC) NA NA 19 20 20 21 22 24 26

High Black

CFM 2292 2238 2158 2049 1935 1840 1732 1635 1513

Heating

Rise (oF) NA NA NA NA 35 37 39 42 45

Heating

Rise (oC) NA NA NA NA 20 21 22 23 25

48VT--A

Table 10 -- Dry Coil Air Delivery* -- Horizontal and Downflow Discharge -- Unit 48VT--A24--60 Cont

UNIT

HEATING

RISE

RANGE

MOTOR

SPEED

WIRE

COLOR

EXTERNAL STATIC PRESSURE (in. W.C.)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

48VT(-,N)A60115 30 - 60oF

(17 - 33oC)

Low Blue

CFM 1448 1362 1296 1226 1168 1108 1071 998 905

Heating

Rise (oF) 60 NA NA NA NA NA NA NA NA

Heating

Rise (oC) 33 NA NA NA NA NA NA NA NA

Med-Low Pink

CFM 1722 1675 1614 1543 1499 1442 1408 1356 1308

Heating

Rise (oF) 50 52 54 56 58 60 NA NA NA

Heating

Rise (oC) 28 29 30 31 32 33 NA NA NA

Medium2Red

CFM 1887 1847 1783 1726 1677 1625 1578 1527 1432

Heating

Rise (oF) 46 47 49 50 52 53 55 57 NA

Heating

Rise (oC) 26 26 27 28 29 30 31 32 NA

Med-High1Orange

CFM 2055 2008 1958 1927 1900 1768 1685 1581 1458

Heating

Rise (oF) 42 43 44 45 46 49 52 55 60

Heating

Rise (oC) 23 24 25 25 25 27 29 31 33

High Black

CFM 2292 2238 2158 2049 1935 1840 1732 1635 1513

Heating

Rise (oF) 38 39 40 42 45 47 50 53 57

Heating

Rise (oC) 21 22 22 24 25 26 28 30 32

48VT(-,N)A60130 35 - 65oF

(19 - 36oC)

Low Blue

CFM 1448 1321 1282 1235 1192 1145 1101 1057 1011

Heating

Rise (oF) NA NA NA NA NA NA NA NA NA

Heating

Rise (oC) NA NA NA NA NA NA NA NA NA

Med-Low Pink

CFM 1722 1675 1614 1543 1499 1442 1408 1356 1308

Heating

Rise (oF) 56 57 60 62 64 NA NA NA NA

Heating

Rise (oC) 31 32 33 35 36 NA NA NA NA

Medium2Red

CFM 1887 1847 1783 1726 1677 1625 1578 1527 1432

Heating

Rise (oF) 51 52 54 56 57 59 61 63 NA

Heating

Rise (oC) 28 29 30 31 32 33 34 35 NA

Med-High1Orange

CFM 2055 2008 1958 1927 1900 1768 1685 1581 1458

Heating

Rise (oF) 47 48 49 50 51 54 57 61 NA

Heating

Rise (oC) 26 27 27 28 28 30 32 34 NA

High Black

CFM 2292 2238 2158 2049 1935 1840 1732 1635 1513

Heating

Rise (oF) 42 43 45 47 50 52 56 59 64

Heating

Rise (oC) 23 24 25 26 28 29 31 33 35

* Air delivery values are without air filter and are for dry coil (See 48VT ---A Wet Coil Pressure Drop table).

1Factory---shipped gas heating speed

2Factory ---shipped heat pump speed

NA --- Not allowed for heating speed

Note: Deduct field---supplied air filter pressure drop and wet coil pressure drop to obtain external static pressure available for ducting.

Shaded areas indicate speed/static combinations that are not permitted for dehumidification speed.

48VT--A

A09068

Fig. 15 -- 208/230--1--60 Wiring Diagram, Unit 48VT--A

48VT--A

A09209

Fig. 16 -- 208/230--3--60 Wiring Diagram, Unit 48VT--A

48VT--A

50VT500173 REV 4.0

A09099

Fig. 17 -- Cooling Charging Table--Subcooling

48VT--A

MAINTENANCE

To ensure continuing high performance and to minimize the

possibility of premature equipment failure, periodic maintenance

must be performed on this equipment. This combination

heating/cooling unit should be inspected at least once each year by

a qualified service person. To troubleshoot cooling or heating of

units, refer to Tables 10, 11 and 12.

NOTE: Consult your local dealer about the availability of a

maintenance contract.

PERSONAL INJURY AND UNIT DAMAGE HAZARD

Failure to follow this warning could result in personal injury

or death and unit component damage.

The ability to properly perform maintenance on this

equipment requires certain expertise, mechanical skills, tools

and equipment. If you do not possess these, do not attempt to

perform any maintenance on this equipment, other than those

procedures recommended in the Owner’s Manual.

!WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow these warnings could result in personal

injury or death:

1. Turn off electrical power to the unit and install a lockout

tag before performing any maintenance or service on this

unit.

2. Use extreme caution when removing panels and parts.

3. Never place anything combustible either on or in contact

with the unit.

4. Should overheating occur or the gas supply fail to shut

off, turn off external main manual gas valve to the unit.

Then shut off electrical supply.

!WARNING

UNIT OPERATION HAZARD

Failure to follow this caution may result in improper

operation.

Errors made when reconnecting wires may cause improper

and dangerous operation. Label all wires prior to

disconnecting when servicing.

CAUTION

The minimum maintenance requirements for this equipment are as

follows:

1. Inspect air filter(s) each month. Clean or replace when

necessary. Certain geographical locations may require more

frequent inspections.

2. Inspect indoor coil, outdoor coil, drain pan, and condensate

drain each cooling season for cleanliness. Clean when

necessary.

3. Inspect blower motor and wheel for cleanliness at the

beginning of each heating and cooling season. Clean when

necessary. For first heating and cooling season, inspect

blower wheel bi--monthly to determine proper cleaning

frequency.

4. Check electrical connections for tightness and controls for

proper operation each heating and cooling season. Service

when necessary. Ensure electrical wiring is not in contact

with refrigerant tubing or sharp metal edges.

5. Check and inspect heating section before each heating

season. Clean and adjust when necessary.

6. Check flue hood and remove any obstructions, if necessary.

Air Filter

IMPORTANT: Never operate the unit without a suitable air filter

in the return--air duct system. Always replace the filter with the

same dimensional size and type as originally installed. (See Table 1

for recommended filter sizes.)

Inspect air filter(s) at least once each month and replace

(throwaway--type) or clean (cleanable--type) at least twice during

each heating and cooling season or whenever the filter(s) becomes

clogged with dust and/or lint.

Indoor Blower and Motor

NOTE: All motors are prelubricated. Do not attempt to lubricate

these motors.

For longer life, operating economy, and continuing efficiency,

clean accumulated dirt and grease from the blower wheel and

motor annually.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury

or death.

Disconnect and tag electrical power to the unit before cleaning

the blower motor and wheel.

!WARNING

Cleaning the Blower Motor and Wheel

1. Remove and disassemble blower assembly as follows:

a. Remove blower access panel (see Fig. 19).

b. Disconnect 5 pin plug and 4 pin plug from indoor

blower motor. Remove capacitor if required.

c. On all units, remove blower assembly from unit.

Remove screws securing blower to blower partition and

slide assembly out. Be careful not to tear insulation in

blower compartment.

d. Ensure proper reassembly by marking blower wheel and

motor in relation to blower housing before disassembly.

e. Loosen setscrew(s) that secures wheel to motor shaft.

Remove screws that secure motor mount brackets to

housing, and slide motor and motor mount out of

housing.

2. Remove and clean blower wheel as follows:

a. Ensure proper reassembly by marking wheel orientation.

b. Lift wheel from housing. When handling and/or

cleaning blower wheel, be sure not to disturb balance

weights (clips) on blower wheel vanes.

c. Remove caked--on dirt from wheel and housing with a

brush. Remove lint and/or dirt accumulations from

wheel and housing with vacuum cleaner, using soft

brush attachment. Remove grease and oil with mild

solvent.

d. Reassemble wheel into housing.

e. Reassemble motor into housing. Be sure setscrews are

tightened on motor shaft flats and not on round part of

shaft. Reinstall blower into unit. Reinstall capacitor.

f. Connect 5 pin plug and 4 pin plug to indoor blower

motor.

g. Reinstall blower access panel (see Fig. 19).

3. Restore electrical power to unit. Start unit and check for

proper blower rotation and motor speeds during heating and

cooling cycles.

48VT--A

Integrated

Gas Unit

Controller

(IGC)

Induced Draft

Motor

Rollout

Switch

Mounting

Screw

Burner

Rack

Inducer

Blower

Housing

Flue

Collector

Box

Interface Fan

Board (IFB)

Auto Transformer

fuses used on 460

volt units only.

(Hidden)

Fan Partition

Mounting

Bracket

A09199

Fig. 18 -- Blower Housing and Flue Collector Box

Compressor

Access Panel

Blower

Access

Panel

Control

Access

Panel

A09210

Fig. 19 -- Unit Access Panels

Induced Draft (combustion air) Blower Assembly

The induced--draft blower assembly consists of the inducer motor,

the blower housing, and the induced--draft blower wheel.

Clean periodically to assure proper airflow and heating efficiency.

Inspect blower wheel every fall and periodically during the heating

season. For the first heating season, inspect blower wheel

bimonthly to determine proper cleaning frequency.

To inspect blower wheel, remove draft hood assembly. Shine a

flashlight into opening to inspect wheel. If cleaning is required,

remove induced--draft blower assembly as follows:

1. Remove control access panel (See Fig. 19).

2. Remove the 5 screws that attach induced--draft blower as-

sembly to the flue collector box cover.

3. Slide the assembly out of the unit. (See Fig. 20). Clean the

blower wheel. If additional cleaning is required, continue

with Steps 4 and 5.

4. To remove blower wheel, remove 2 setscrews.

5. To remove inducer motor, remove screws that hold the

inducer motor to the blower housing.

6. To reinstall, reverse the procedure outlined above.

Flue Gas Passageways

To inspect the flue collector box and upper areas of the heat

exchanger:

1. Remove the induced draft blower assembly according to

directions in the Induced Draft Blower Assembly section.

2. Remove the 11 screws holding the flue collector box cover

(See Fig. 18) to the heat exchanger assembly. Inspect the

heat exchangers.

3. Clean all surfaces, as required, using a wire brush.

Limit Switch

Remove blower access panel (see Fig. 19). Limit switch is located

on the fan partition.

Burner Ignition

Unit is equipped with a direct spark ignition 100 percent lockout

system. Ignition module (IGC) is located in the control box (See

Fig. 18). Module contains a self--diagnostic LED. During

servicing, refer to label diagram or Table 5 in these instructions for

LED interpretation.

If lockout occurs, unit may be reset by either momentarily

interrupting power supply to unit or by turning selector switch to

OFF position at the thermostat.

Main Burners

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.

Removal of Gas Train

To remove the gas train for servicing:

1. Shut off main gas valve.

2. Shut off power to unit and install lockout tag.

3. Remove control access panel (See Fig. 19).

4. Disconnect gas piping at unit gas valve.

5. Remove fan partition mounting bracket (2 screws located

on the left side of control compartment on the fan partition

panel). Slide bracket forward, bottom first to remove. (See

Fig. 18).

6. Remove wires connected to gas valve. Mark each wire.

7. Remove ignitor and sensor wires at the ignitor module.

8. Remove the mounting screw that attaches the burner rack to

the unit base (See Fig. 18).

9. Slide the burner rack out of the unit (See Fig. 18 and 21).

10. To reinstall, reverse the procedure outlined above.

Outdoor Coil, Indoor Coil, and Condensate Drain Pan

Inspect the outdoor coil, indoor coil, and condensate drain pan at

least once each year. The coils are easily cleaned when dry;

therefore, inspect and clean the coils either before or after each

cooling season. Remove all obstructions, including weeds and

shrubs, that interfere with the airflow through the condenser coil.

Straighten bent fins with a fin comb. If coated with dirt or lint,

clean the coils with a vacuum cleaner, using the soft brush

attachment. Be careful not to bend the fins. If coated with oil or

grease, clean the coils with a mild detergent--and--water solution.

Rinse coils with clear water, using a garden hose. Be careful not to

splash water on motors, insulation, wiring, or air filter(s). For best

results, spray outdoor coil fins from inside to outside the unit. On

units with an outer and inner condenser coil, be sure to clean

between the coils. Be sure to flush all dirt and debris from the unit

base.

Inspect the drain pan and condensate drain line when inspecting

the coils. Clean the drain pan and condensate drain by removing all

foreign matter from the pan. Flush the pan and drain tube with

clear water. Do not splash water on the insulation, motor, wiring, or

air filter(s). If the drain tube is restricted, clear it with a “plumbers

snake” or similar probe device. Ensure that the auxiliary drain port

above the drain tube is also clear.

48VT--A

BLOWER

HOUSING

2 SETSCREWS

(HIDDEN)

C99085

Fig. 20 -- Removal of Motor and Blower Wheel

A07680

Fig. 21 -- Burner Rack Removed

FEEDER TUBE

STUB TUBE

DEFROST

THERMOSTAT

C99029

Fig. 22 -- Defrost Thermostat Location

Outdoor Fan

UNIT OPERATION HAZARD

Failure to follow this caution may result in damage to unit

components.

Keep the outdoor fan free from all obstructions to ensure

proper cooling operation. Never place articles on top of the

unit.

CAUTION

1. Remove 6 screws holding outdoor grille and motor to top

cover.

2. Turn motor/grille assembly upside down on top cover to

expose the fan blade.

3. Inspect the fan blades for cracks or bends.

4. If fan needs to be removed, loosen the setscrew and slide the

fan off the motor shaft.

5. When replacing fan blade, position blade back to the same

position as before.

6. Ensure that setscrew engages the flat area on the motor shaft

when tightening.

7. Replace grille.

Electrical Controls and Wiring

Inspect and check the electrical controls and wiring annually. Be

sure to turn off the gas supply, and then the electrical power to the

unit.

Remove access panels (see Fig. 19) to locate all the electrical

controls and wiring. Check all electrical connections for tightness.

Tighten all screw connections. If any discolored or burned

connections are noticed, disassemble the connection, clean all the

parts, re--strip the wire end and reassemble the connection properly

and securely.

After inspecting the electrical controls and wiring, replace the

access panels (see Fig. 19). Start the unit, and observe at least one

complete heating cycle and one complete cooling cycle to ensure

proper operation. If discrepancies are observed in any operating

cycle, or if a suspected malfunction has occurred, check each

electrical component with the proper electrical instrumentation.

Refer to the unit wiring label when making these checkouts.

NOTE: Refer to the heating and/or cooling sequence of operation

in this publication as an aid in determining proper control

operation.

Refrigerant Circuit

Annually inspect all refrigerant tubing connections and the unit

base for oil accumulations. Detecting oil generally indicates a

refrigerant leak.

EXPLOSION, PERSONAL INJURY AND

ENVIRONMENTAL HAZARD

Failure to follow this warning could result in personal injury,

death or property damage.

System under pressure. Relieve pressure and recover all

refrigerant before system repair or final unit disposal. Use all

service ports and open all flow--control devices, including

solenoid valves.

!WARNING

If oil is detected or if low cooling performance is suspected,

leak--test all refrigerant tubing using an electronic leak--detector,

halide torch, or liquid--soap solution. If a refrigerant leak is

detected, refer to the Check for Refrigerant Leaks section.

48VT--A

If no refrigerant leaks are found and low cooling performance is

suspected, refer to the Checking and Adjusting Refrigerant Charge

section.

Gas Input

The gas input does not require checking unless improper heating

performance is suspected. If a problem exists, refer to the Start--Up

section.

Indoor Airflow

The heating and/or cooling airflow does not require checking

unless improper performance is suspected. If a problem exists, be

sure that all supply-- and return--air grilles are open and free from

obstructions, and that the air filter is clean. When necessary, refer to

the Indoor Airflow and Airflow Adjustments section to check the

system airflow.

Check Defrost Thermostat

The defrost thermostat is usually located on the lowest liquid

leaving circuit of the left condenser coil (see Fig. 22). The

thermostat closes at 32_F(0_C) and opens at 65_F(18_C).

Puron Items

Metering Device (Thermostatic Expansion Valve &

Piston)

This unit uses both a hard shutoff, balance port TXV in the indoor

coil and a piston in each side of the outdoor coil. The TXV

maintains a constant superheat at the evaporator coil exit (cooling

mode) resulting in higher overall system efficiency.

Pressure Switches

Pressure switches are protective devices wired into control circuit

(low voltage). They shut off compressor if abnormally high or low

pressures are present in the refrigeration circuit. These pressure

switches are specifically designed to operate with Puron (R--410A)

systems. R--22 pressure switches must not be used as replacements

for the Puron (R--410A) system.

Loss of Charge Switch

This switch is located on the liquid line and protects against low

suction pressures caused by such events as loss of charge, low

airflow across indoor coil, dirty filters, etc. It opens on a pressure

drop at about 20 psig. If system pressure is above this, switch

should be closed. To check switch:

1. Turn off all power to unit.

2. Disconnect leads on switch.

3. Apply ohm meter leads across switch. You should have

continuity on a good switch.

NOTE: Because these switches are attached to refrigeration

system under pressure, it is not advisable to remove this device for

troubleshooting unless you are reasonably certain that a problem

exists. If switch must be removed, remove and recover all system

charge so that pressure gauges read 0 psi. Never open system

without breaking vacuum with dry nitrogen.

High--Pressure Switch

The high--pressure switch is located in the discharge line and

protects against excessive condenser coil pressure. It opens at 650

psig.

High pressure may be caused by a dirty outdoor coil, failed fan

motor, or outdoor air recirculation. To check switch:

1. Turn off all power to unit.

2. Disconnect leads on switch.

3. Apply ohm meter leads across switch. You should have

continuity on a good switch.

48VT--A

OF2

OF1

QUIET

SHIFT

120

INTERVAL TIMER OFF

DFT

O R W

Y C

T2 C C O

DFT

T1 Y P1 J1

SPEEDUP

Speedup

Pins

Defrost interval

DIP switches

Quiet

Shift

A08020

Fig. 23 -- Defrost Control

Copeland Scroll Compressor (Puron Refrigerant)

The compressor used in this product is specifically designed to

operate with Puron (R--410A) refrigerant and cannot be

interchanged.

The compressor is an electrical (as well as mechanical) device.

Exercise extreme caution when working near compressors. Power

should be shut off, if possible, for most troubleshooting techniques.

Refrigerants present additional safety hazards.

EXPLOSION HAZARD

Failure to follow this warning could result in personal injury

or death and/or property damage.

Wear safety glasses and gloves when handling refrigerants.

Keep torches and other ignition sources away from

refrigerants and oils.

!WARNING

The scroll compressor pumps refrigerant throughout the system by

the interaction of a stationary and an orbiting scroll. The scroll

compressor has no dynamic suction or discharge valves, and it is

more tolerant of stresses caused by debris, liquid slugging, and

flooded starts. The compressor is equipped with an internal

pressure relief port. The pressure relief port is a safety device,

designed to protect against extreme high pressure. The relief port

has an operating range between 550 and 625 psi differential

pressure.

48VT--A

C99097

Fig. 24 -- Refrigerant Circuit

COMPRESSOR

ACCUMULATOR

OUTDOOR COIL INDOOR COIL

LCS

LEGEND

HPS – High Pressure Switch

LCS – Loss of Charge Switch

Accurater

Metering De vice

Arrow indicates direction of flo w

TXV in Metering

Position

Bypass

Position

HP S

C03011

Fig. 25 -- Typical Heat Pump Operation, Cooling Mode

48VT--A

COMPRESSOR

ACCUMULATOR

OUTDOOR COIL INDOOR COIL

LCS

LEGEND

HPS – High Pressure Switch

LCS – Loss of Charge Switch

Accurater

®

Metering De vice

Arrow indicates direction of flo w

TXV in Bypass

Position

Metering

Position

HP S

C03012

Fig. 26 -- Typical Heat Pump Operation, Heating Mode

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could result in personal injury

or equipment damage.

This system uses Puron (R--410A) refrigerant which has

higher operating 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.

If you are unsure, consult the equipment manufacturer.

WARNING

Refrigerant System

This information covers the refrigerant system of the 48VT--A

including the compressor oil needed, servicing systems on roofs

containing synthetic materials, the filter drier and refrigerant

charging.

Compressor Oil

If additional oil is needed use Uniqema RL32--3MAF. If this oil is

not available, use Copeland Ultra 32CC or Mobil Artic EAL22CC.

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. Take all necessary

precautions to avoid exposure of the oil to the atmosphere.

Servicing Systems on Roofs and with Synthetic materials

POE (polyolester) compressor lubricants are known to cause long

term damage to some synthetic roofing materials.

Exposure, even if immediately cleaned up, may cause

embrittlement (leading to cracking) to occur in one year or more.

When performing any service that may risk exposure of

compressor oil to the roof, take appropriate precautions to protect

roofing. Procedures which risk oil leakage include, but are not

limited to, compressor replacement, repairing refrigerant leaks,

replacing refrigerant components such as filter drier, pressure

switch, metering device, coil, accumulator, or reversing valve.

Synthetic Roof Precautionary Procedure

1. Cover extended roof working area with an impermeable

polyethylene (plastic) drip cloth or tarp. Cover an

approximate 10x10 ft (3x3 m) area.

2. Cover area in front of the unit service panel with a terry

cloth shop towel to absorb lubricant spills and prevent

run--offs, and protect drop cloth from tears caused by tools

or components.

3. Place terry cloth shop towel inside unit immediately under

component(s) to be serviced and prevent lubricant run--offs

through the louvered openings in the unit base.

4. Perform required service.

5. Remove and dispose of any oil contaminated material per

local codes.

Liquid Line Filter Drier

This filter drier is specifically designed to operate with Puron. Use

only factory--authorized components. Filter drier must be replaced

whenever the refrigerant system is opened. When removing a filter

drier, use a tubing cutter to cut the drier from the system. Do not

unsweat a filter drier from the system. Heat from unsweating will

release moisture and contaminants from drier into system.

Puron (R--410A) Refrigerant Charging

Refer to unit information plate and charging chart. Some R--410A

refrigerant cylinders contain a dip tube to allow liquid refrigerant to

flow from cylinder in upright position. For cylinders equipped

with a dip tube, charge Puron units with cylinder in upright

position and a commercial metering device in manifold hose.

Charge refrigerant into suction--line.

TROUBLESHOOTING

Use the Troubleshooting Guides (See Tables 10--12) if problems

occur with these units.

START--UP CHECKLIST

Use Start--Up checklist to ensure proper start--up procedures are

followed.

48VT--A

PURONR(R--410A) QUICK REFERENCE GUIDE

SPuron refrigerant operates at 50--70 percent higher pressures than R--22. Be sure that servicing equipment and replacement

components are designed to operate with Puron

SPuron refrigerant cylinders are rose colored.

SRecovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.

SPuron systems should be charged with liquid refrigerant. Use a commercial type metering device in the manifold hose when

charging into suction line with compressor operating

SManifold sets should be minimum 700 psig high side and 180 psig low side with 550 psig low--side retard.

SUse hoses with minimum 700 psig service pressure rating.

SLeak detectors should be designed to detect HFC refrigerant.

SPuron, as with other HFCs, is only compatible with POE oils.

SVacuum pumps will not remove moisture from oil.

SDo not use liquid--line filter driers with rated working pressures less than 600 psig.

SDo not leave Puron suction line filter driers in line longer than 72 hrs.

SDo not install a suction--line filter drier in liquid line.

SPOE oils absorb moisture rapidly. Do not expose oil to atmosphere.

SPOE oils may cause damage to certain plastics and roofing materials.

SWrap all filter driers and service valves with wet cloth when brazing.

SA factory approved liquid--line filter drier is required on every unit.

SDo NOT use an R--22 TXV.

SNever open system to atmosphere while it is under a vacuum.

SWhen system must be opened for service, recover refrigerant, evacuate then break vacuum with dry nitrogen and replace filter

driers. Evacuate to 500 microns prior to recharging.

SDo not vent Puron into the atmosphere.

SObserve all warnings,cautions,andbold text.

SAll indoor coils must be installed with a hard shutoff Puron TXV metering device.

48VT--A

Table 11 – Troubleshooting Guide -- Cooling or Heat Pump Heating Mode

SYMPTOM CAUSE REMEDY

Compressor and Outdoor fan will not

start.

Power Failure Call power company.

Fuse blown or circuit breaker tripped Replacefuseorresetcircuitbreaker.

Defective thermostat, contactor, transformer, or control

relay Replace component.

Insufficient line voltage Determine cause and correct.

Incorrect or faulty wiring Check wiring diagram and rewire correctly.

Thermostat setting too high Lower thermostat setting below room temperature.

Compressor will not start but Outdoor

fan runs.

Faulty wiring or loose connections in compressor circuit Check wiring and repair or replace.

Compressor motor burned out, seized, or internal over-

load open Determine cause Replace compressor.

Defective run/start capacitor, overload, start relay Determine cause and replace.

Onelegof3---phasepowerdead Replace fuse or reset circuit breaker. Determine

cause.

Three--- phase scroll compressor makes

excessive noise, and there may

be a low pressure differential.

Scroll compressor is rotating in the wrong direction Correct the direction of rotation by reversing the

3---phase power leads to the unit.

Compressor cycles (other than normally

satisfying thermostat).

Refrigerant overcharge or undercharge Recover refrigerant, evacuate system, and recharge

to capacities shown on nameplate.

Defective compressor Replace and determine cause.

Insufficient line voltage Determine cause and correct.

Blocked Outdoor Determine cause and correct.

Defective run/start capacitor, overload or start relay Determine cause and replace.

Defective thermostat Replace thermostat.

Faulty Outdoor ---fan motor or capacitor Replace.

Damaged reversing valve Determine cause and correct

Restriction in refrigerant system Locate restriction and remove.

Compressor operates continuously.

Dirty air filter Replace filter.

Unit undersized for load Decrease load or increase unit size.

Thermostat set too low Reset thermostat.

Low refrigerant charge Locate leak, repair, and recharge.

Mechanical damage in compressor. Replace compressor.

Air in system Recover refrigerant, evacuate system, and recharge.

Frosted coil with incorrect defrost operation

Check defrost time settings, Reset as necessary

Check defrost temperature switch, Replace as nec-

essary

Outdoor coil dirty or restricted Clean coil or remove restriction .

Excessive head pressure.

Dirty air filter Replace filter.

Dirty Indoor or Outdoor coil Clean coil.

Refrigerant overcharged Recover excess refrigerant.

Air in system Recover refrigerant, evacuate system, and recharge.

Indoor or Outdoor air restricted or air short---cycling Determine cause and correct.

Head pressure too low.

Low refrigerant charge Check for leaks, repair, and recharge.

Compressor IPR leaking Replace compressor.

Restrictioninliquidtube Remove restriction.

Excessive suction pressure.

High heat load Check for source and eliminate.

Compressor IPR leaking Replace compressor.

Refrigerant overcharged Recover excess refrigerant.

Reversing valve hung up or leaking internally Replace valve

Suction pressure too low.

Dirty air filter Replace Filter.

Low refrigerant charge Check for leaks, repair, and recharge.

Metering device or low side restricted Remove source of restriction.

Insufficient Indoor airflow Increase air quantity. Check filter — replace if neces-

sary.

Temperature too low in conditioned area Reset thermostat.

Outdoor ambient below 55°F (12.8°C) Install low ---ambient kit.

Field --- installed filter ---drier restricted Replace.

(Heat) Outdoor coil frosted Move timer on control board to 30 minutes between

defrost cycles

Compressor runs but outdoor fan does

not NC (normally closed) contacts on defrost board open Check condition of relay on board Replace if neces-

sary

48VT--A

Table 12 – Troubleshooting Guide–Heating

SYMPTOM CAUSE REMEDY

Burners will not ignite

Water in gas line Drain. Install drip leg.

No power to furnace Check power supply fuses, wiring or circuit breaker.

No 24--v power supply to control circuit

Check transformer.

NOTE: Some transformers have internal over--current protection

that requires a cool--down period to reset.

Mis--wired or loose connections Check all wiring and wire nut connections

Misaligned spark electrodes Check flame ignition and sense electrode positioning.

Adjust as necessary.

No gas at main burners

1. Check gas line for air. Purge as necessary. NOTE: After purging

gas line of air, wait at least 5 minutes for any gas to dissipate be-

fore attempting to light unit.

2. Check gas valve.

Inadequate heating

Dirty air filter Clean or replace filter as necessary

Gas input to furnace too low Check gas pressure at manifold match with that on unit nameplate

Unit undersized for application Replace with proper unit or add additional unit

Restricted airflow Clean or replace filter. Remove any restriction.

Limit switch cycles main burners Check rotation of blower, temperature rise of unit. Adjust as neces-

sary.

Poor flame characteristics Incomplete combustion results in: Aldehyde odors,

carbon monoxide, sooting flame, floating flame

1. Tighten all screws around burner compartment

2. Cracked heat exchanger. Replace.

3. Unit over--fired. Reduce input (change orifices or adjust gas line

or manifold pressure).

4. Check burner alignment.

5. Inspect heat exchanger for blockage. Clean as necessary.

Table 13 – Troubleshooting Guide–LED Status Codes

SYMPTOM CAUSE REMEDY

No Power Hardware failure

(LED OFF) Loss of power to control module (IGC)*.

Check 5--amp fuse son IGC*, power to unit, 24--v circuit breaker,

and transformer. Units without a 24--v circuit breaker have an

internal overload in the 24--v transformer. If the overload trips,

allow 10 minutes for automatic reset.

Limit switch faults

(LED 2 flashes) High temperature limit switch is open.

Check the operation of the indoor (evaporator) fan motor. Ensure

that the supply--air temperature rise is in accordance with the

range on the unit nameplate. Clean or replace filters.

Flame sense fault

(LED 3 flashes) The IGC* sensed flame that should not be present. Reset unit. If problem persists, replace control board.

4 consecutive limit switch

faults

(LED 4 flashes)

Inadequate airflow to unit.

Check the operation of the indoor (evaporator) fan motor and that

supply--air temperature rise agrees with range on unit nameplate

information.

Ignition lockout

(LED 5 flashes) Unit unsuccessfully attempted ignition for 15 minutes.

Check ignitor and flame sensor electrode spacing, gaps, etc.

Ensure that fame sense and ignition wires are properly terminated.

Verify that unit is obtaining proper amount of gas.

Pressure Switch motor fault

(LED 6 flashes) Open pressure switch.

Verify wiring connections to pressure switch and inducer motor.

Verify pressure switch hose is tightly connected to both inducer

housing and pressure switch. Verify inducer wheel is properly

attached to inducer motor shaft. Verify inducer motor shaft is turn-

ing.

Rollout switch fault

(LED 7 flashes) Rollout switch has opened.

Rollout switch will automatically reset, but IGC* will continue to

lockout unit. Check gas valve operation. Ensure that induced--draft

blower wheel is properly secured to motor shaft. Inspect heat

exchanger. Reset unit at unit disconnect.

Internal control fault

(LED 8 flashes)

Microprocessor has sensed an error in the software

or hardware.

If error code is not cleared by resetting unit power, replace the

IGC*.

Temporary 1 hr auto reset

(LED 9 flashes) Electrical interference impeding IGC software Reset 24--v. to control board or turn thermostat off, then on again.

Fault will automatically reset itself in one (1) hour.

*WARNING :If the IGC must be replaced, be sure to ground yourself to dissipate any electrical charge that my be present before handling new control

board. The IGC is sensitive to static electricity and my be damaged if the necessary precautions are not taken.

IMPORTANT: Refer to Table 12 ---Troubleshooting Guide ---Heating for additional troubleshooting analysis.

LEGEND

IGC—Integrated Gas Unit Controller

LED—Light---Emitting Diode

48VT--A

START--UP CHECKLIST

(Remove and Store in Job Files)

I. PRELIMINARY INFORMATION

MODEL NO.:

SERIAL NO.:

DATE:

TECHNICIAN:

II. PRESTART--UP (Insert check mark in box as each item is completed)

( ) VERIFY THAT ALL PACKING MATERIALS HAVE BEEN REMOVED FROM UNIT

( ) REMOVE ALL SHIPPING HOLD DOWN BOLTS AND BRACKETS PER INSTALLATION INSTRUCTIONS

( ) CHECK ALL ELECTRICAL CONNECTIONS AND TERMINALS FOR TIGHTNESS

( ) CHECK GAS PIPING FOR LEAKS (WHERE APPLICABLE)

( ) CHECK THAT INDOOR (EVAPORATOR) AIR FILTER IS CLEAN AND IN PLACE

( ) VERIFY THAT UNIT INSTALLATION IS LEVEL

( ) CHECK FAN WHEEL, AND PROPELLER FOR LOCATION IN HOUSING/ORIFICE AND SETSCREW TIGHTNESS

III. START--UP

ELECTRICAL

SUPPLY VOLTAGE

COMPRESSOR AMPS

INDOOR (EVAPORATOR) FAN AMPS

TEMPERATURES

OUTDOOR (CONDENSER) AIR TEMPERATURE DB

RETURN--AIR TEMPERATURE DB WB

COOLING SUPPLY AIR DB WB

HEAT PUMP SUPPLY AIR__________________

GAS HEAT SUPPLY AIR

PRESSURES

GAS INLET PRESSURE IN. W.C.

GAS MANIFOLD PRESSURE IN. W.C.

REFRIGERANT SUCTION PSIG, SUCTION LINE TEMP*

REFRIGERANT DISCHARGE PSIG, LIQUID TEMP{

( ) VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS

GAS HEAT TEMPERATURE RISE

TEMPERATURE RISE (See Literature) RANGE

MEASURED TEMPERATURE RISE

* Measured at suction inlet to compressor

{Measured at liquid line leaving condenser.

48VT--A

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

Catalog No: 48VT---05SI

Replaces: 48VT---04SI

48VT--A

Carrier 48Vtn Users Manual 48VT 05SI

48VT(N) 48VT-05SI

48VT(N) to the manual d54aa3ff-51b5-4b7c-880c-3404ca198c64

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