Carrier Single Package Rooftop Units Electric Cooling Gas Heating 48Ej Users Manual

48EJ to the manual b9a43d94-fd73-49a9-aa7f-83f77933caab

2015-01-24

: Carrier Carrier-Single-Package-Rooftop-Units-Electric-Cooling-Gas-Heating-48Ej-Users-Manual-310812 carrier-single-package-rooftop-units-electric-cooling-gas-heating-48ej-users-manual-310812 carrier pdf

Open the PDF directly: View PDF .
Page Count: 64

Download
Open PDF In Browser	View PDF

48EJ,EK,EW,EY024-048
Single Package Rooftop Units
Electric Cooling/Gas Heating

Installation, Start-Up and
Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31
Step 1 — Provide Unit Support . . . . . . . . . . . . . . . 1
• ROOF CURB
• ALTERNATE UNIT SUPPORT
Step 2 — Rig and Place Unit . . . . . . . . . . . . . . . . . . 2
• POSITIONING
• ROOF MOUNT
Step 3 — Field Fabricate Ductwork . . . . . . . . . . . . 2
Step 4 — Install Flue Hood . . . . . . . . . . . . . . . . . . 12
Step 5 — Trap Condensate Drain . . . . . . . . . . . . 13
Step 6 — Install Gas Piping . . . . . . . . . . . . . . . . . . 13
Step 7 — Controls Options . . . . . . . . . . . . . . . . . . 13
• CONSTANT VOLUME APPLICATIONS
• VARIABLE AIR VOLUME (VAV) APPLICATIONS
Step 8 — Make Electrical Connections . . . . . . . 16
• POWER WIRING
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
Step 9 — Make Outdoor-Air Inlet
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
• ECONOMIZER
• ECONOMIZER SETTINGS
Step 10 — Position Power Exhaust/Barometric
Relief Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Step 11 — Install All Accessories . . . . . . . . . . . . 30
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-44
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-55
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . 56-61
START-UP CHECKLIST . . . . . . . . . . . . . . . . CL-1,CL-2

1. Improper installation, adjustment, alteration, service, or maintenance can cause property damage, personal injury, or loss of life. Refer to the User’s
Information Manual provided with this unit for more
details.
2. Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance.
What to do if you smell gas:
1. DO NOT try to light any appliance.
2. DO NOT touch any electrical switch, or use any phone
in your building.
3. IMMEDIATELY call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
4. If you cannot reach your gas supplier, call the fire
department.

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

INSTALLATION
Step 1 — Provide Unit Support

SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical components. Only trained and qualified service personnel should
install, repair, or service air-conditioning equipment.
Untrained personnel can perform the basic maintenance
functions of cleaning coils and filters and replacing filters.
All other operations should be performed by trained service
personnel. When working on air-conditioning equipment, observe precautions in the literature, tags and labels attached
to the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work gloves.
Use quenching cloth for unbrazing operations. Have fire extinguishers available for all brazing operations.

Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.

1. All panels must be in place when rigging.
2. Unit is not designed for handling by fork truck.
ROOF CURB — Assemble or install accessory roof curb in
accordance with instructions shipped with this accessory. See
Fig. 1 and 2. Install insulation, cant strips, roofing, and counter
flashing as shown. Ductwork can be installed to roof curb
before unit is set in place. Curb should be level. This is necessary to permit unit drain to function properly. Unit leveling tolerance is shown in Fig. 1 and 2. Refer to Accessory
Roof Curb Installation Instructions for additional information as required. When accessory roof curb is used, unit may
be installed on class A, B, or C roof covering material.
IMPORTANT: The gasketing of the unit to the roof
curb is critical for a watertight seal. Install gasket with
the roof curb as shown in Fig. 1 and 2. Improperly
applied gasket can also result in air leaks and poor unit
performance.

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
PC 111
Catalog No. 564-962
Printed in U.S.A.
Form 48E-5SI
Pg 1
8-97
Replaces: 48E-3SI
Tab 1a

ALTERNATE UNIT SUPPORT — When the preferred curb
or slab mount cannot be used, support unit with sleepers on
perimeter, using unit curb support area. If sleepers cannot be
used, support long sides of unit (refer to Fig. 3-6) with a
minimum number of 4-in. x 4-in. pads spaced as follows:
48EJ,EK,EW,EY024-034 units require 3 pads on each side;
48EJ,EK,EW,EY038-048 units require 4 pads on each side.
Unit may sag if supported by corners only.

Step 3 — Field Fabricate Ductwork
48EJ,EK UNITS — Field-fabricated ductwork should be attached to the roof curb. Supply and return duct dimensions
are shown in Fig. 3 and 4. Air distribution is shown in
Fig. 8.
To attach ductwork to roof curb, insert duct approximately 10 to 11 in. up into roof curb. Connect ductwork to
14-gage roof curb material with sheet metal screws driven
from inside the duct.
Secure all ducts to the building structure, using flexible
duct connectors between roof curb and ducts as required. Ducts
passing through an unoccupied space must be insulated and
covered with a vapor barrier. Outlet grilles must not lie
directly below unit discharge. The return duct must have a
90-degree elbow before opening into the building space if
the unit is equipped with power exhaust.

Step 2 — Rig and Place Unit — Inspect unit for transportation damage. File any claim with transportation agency.
Do not drop unit; keep upright. Use spreader bars over
unit to prevent sling or cable damage. Level by using unit
frame as a reference; leveling tolerance is shown in Fig. 1
and 2. See Fig. 7 for additional information. Unit operating
weight is shown in Table 1.
NOTE: On retrofit jobs, ductwork may be attached to old
unit instead of roof curb. Be careful not to damage ductwork
when removing old unit. Attach existing ductwork to roof
curb instead of unit.
Four lifting lugs are provided on the unit base rails as shown
in Fig. 7. Refer to rigging instructions on unit.

For vertical supply and return units, tools or parts could
drop into ductwork and cause an injury. Install 90 degree elbow turns in the supply and return ductwork between the unit and the conditioned space. If a 90 degree
elbow cannot be installed, then grilles of sufficient strength
and density should be installed to prevent objects from
falling into the conditioned space.

POSITIONING — Maintain clearance, per Fig. 3-6, around
and above unit to provide minimum distance from combustible materials, proper airflow, and service access.
Do not install unit in an indoor location. Do not locate
unit air inlets near exhaust vents or other sources of contaminated air. For proper unit operation, adequate combustion and ventilation air must be provided in accordance with
Section 5.3 (Air for Combustion and Ventilation) of the
National Fuel Gas Code, ANSI Z223.1 (American National
Standards Institute).
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
Locate mechanical draft system flue assembly at least
4 ft from any opening through which combustion products
could enter the building, and at least 4 ft from any adjacent
building. When unit is located adjacent to public walkways,
flue assembly must be at least 7 ft above grade.

48EW,EY UNITS — Remove shipping covers from supply
and return air openings. Attach field-supplied ductwork to
unit. Use a single duct over both return openings and a single
duct over both supply openings. See Fig. 5 and 6 for duct
opening dimensions. Secure all ducts to the building structure. See Fig. 9. Use flexible duct connectors between unit
and ducts as required. Insulate and weatherproof all external
ductwork, joints, and building 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.
Install accesssory barometric relief or power exhaust in
the field-fabricated return ductwork. Refer to Position Power
Exhaust/Barometric Relief Damper Hood section on
page 26 for more information.

ROOF MOUNT — Check building codes for weight distribution requirements. Unit weight is shown in Table 1.

Instructions continued on page 12.

NOTES:
1. All roof curb parts are to be 16 ga galvanized steel.
2. Dimensions are in inches.
3. To prevent standing water in the drain pan of the indoor
section and the heat exchangers, unit can only be pitched
as shown.

UNIT LEVELING TOLERANCES DIMENSIONS*
(Degrees and Inches)
A
Deg.
1.0

B
in.
2.9

Deg.
.50

*From edge of unit to horizontal.

Fig. 1 — Roof Curb (Sizes 024-034)
3

in.
.75

UNIT LEVELING TOLERANCES DIMENSIONS*
(Degrees and Inches)
A
Deg.
1.0

B
in.
2.9

Deg.
.50

*From edge of unit to horizontal.

Fig. 2 — Roof Curb (Sizes 038-048)

in.
.75

VFD — Variable Frequency Drive
NOTES:
1. Weights include economizer (STD).
2.
Center of gravity.
3. Do not locate adjacent units with flue discharge facing economizer inlet. Minimum clearances to be:
Adjacent Units: 158-09
Top of Units: No overhang
Condenser Coil: 48-09
Economizer Side: 68-09
Gas Heat Side: 48-09
Filter Access Side: 108-09 (For Removal of
Evaporator Coil)
4. For smaller service and operational clearances, contact Carrier Application Engineering department.
5. Bottom ducts designed to be attached to accessory roof curb. If unit is mounted on dunnage, it is recommended the ducts be
supported by cross braces as done on accessory roof curb.
6. Dimensions are in inches.

UNIT
SIZE
48EJ,EKD024
48EJE024
48EJ,EKD028
48EJE028
48EJ,EKD030
48EJE030
48EJ,EKD034
48EJE034

OPERATING
WEIGHT
lb
4176
4256
4262
4342
4262
4342
4262
4342

ft-in.
6- 03⁄8
6- 15⁄16
5- 95⁄8
5-101⁄8
5- 95⁄8
5-101⁄8
5- 95⁄8
5-101⁄8

ft-in.
3-63⁄8
3-611⁄16
3-8
3-85⁄16
3-8
3-85⁄16
3-8
3-85⁄16

CORNER WEIGHT (lb)
1
879
917
899
929
899
929
899
929

2
954
973
899
916
899
916
899
916

3
1220
1218
1232
1240
1232
1240
1232
1240

4
1124
1148
1232
1257
1232
1257
1232
1257

Fig. 3 — Base Unit Dimensions, 48EJ,EK024-034
5

VFD — Variable Frequency Drive

OPERATING
WEIGHT
lb
48EJ,EKD038
4442
48EJE038
4602
48EJ,EKD044
4668
48EJE044
4828
48EJ,EKD048
4955
48EJE048
5115
UNIT
SIZE

NOTES:
1. Weights include economizer (STD).
2.
Center of gravity.
3. Do not locate adjacent units with flue discharge facing economizer inlet. Minimum clearances to be:
Adjacent Units: 158-09
Top of Units: No overhang
Condenser Coil: 48-09
Economizer Side: 68-09
Gas Heat Side: 48-09
Filter Access Side: 108-09 (For Removal of Evaporator Coil)
4. For smaller service and operational clearances, contact
Carrier Application Engineering department.
5. Bottom ducts designed to be attached to accessory roof curb.
If unit is mounted on dunnage, it is recommended the ducts be
supported by cross braces as done on accessory roof curb.
6. Dimensions are in inches.

ft-in.
7- 811⁄16
7-101⁄8
7- 55⁄16
7- 613⁄16
7- 311⁄16
7- 53⁄16

ft-in.
3-107⁄8
3-113⁄16
3-107⁄8
3-113⁄16
3-101⁄2
3-1013⁄16

Fig. 4 — Base Unit Dimensions, 48EJ,EK038-048

CORNER WEIGHT (lb)
1
1021
1080
1033
1094
1068
1129

2
894
934
906
945
953
994

3
1180
1200
1275
1293
1384
1401

4
1347
1388
1455
1496
1550
1592

VFD — Variable Frequency Drive
UNIT
SIZE

NOTES:
1. Weights include economizer (STD).
2.

Center of gravity.

3. Do not locate adjacent units with flue discharge facing economizer inlet.
Minimum clearances to be:
Adjacent Units: 158-09
Top of Units: No overhang
Condenser Coil: 48-09
Economizer Side: 68-09
Gas Heat Side: 48-09
Filter Access Side: 108-09 (For Removal of Evaporator Coil)
4. For smaller service and operational clearances, contact Carrier
Application Engineering department.
5. Dimensions are in inches.
6. For side-supply/return applications, a single return and supply ductwork
connection is recommended for covering both return and both supply
openings.

48EW,EYD024
48EWE024
48EW,EYD028
48EWE028
48EW,EYD030
48EWE030
48EW,EYD034
48EWE034

OPERATING
WEIGHT
lb
4176
4256
4262
4342
4262
4342
4262
4342

ft-in.
6- 03⁄8
6- 15⁄16
5- 95⁄8
5-101⁄8
5- 95⁄8
5-101⁄8
5- 95⁄8
5-101⁄8

ft-in.
3-63⁄8
3-611⁄16
3-8
3-85⁄16
3-8
3-85⁄16
3-8
3-85⁄16

Fig. 5 — Base Unit Dimensions, 48EW,EY024-034

CORNER WEIGHT (lb)
1
879
917
899
929
899
929
899
929

2
954
973
899
916
899
916
899
916

3
1220
1218
1232
1240
1232
1240
1232
1240

4
1124
1148
1232
1257
1232
1257
1232
1257

VFD — Variable Frequency Drive
UNIT
SIZE

NOTES:
1. Weights include economizer (STD).
2.

Center of gravity.

3. Do not locate adjacent units with flue discharge facing economizer
inlet. Minimum clearances to be:
Adjacent Units: 158-09
Top of Units: No overhang
Condenser Coil: 48-09
Economizer Side: 68-09
Gas Heat Side: 48-09
Filter Access Side: 108-09 (For Removal of Evaporator Coil)
4. For smaller service and operational clearances, contact Carrier
Application Engineering department.
5. Dimensions are in inches.
6. For side-supply/return applications, a single return and supply ductwork connection is recommended for covering both return and both
supply openings.

48EW,EYD038
48EWE038
48EW,EYD044
48EWE044
48EW,EYD048
48EWE048

OPERATING
WEIGHT
lb
4442
4602
4668
4828
4955
5115

ft-in.
7- 811⁄16
7-101⁄8
7- 55⁄16
7- 613⁄16
7- 311⁄16
7- 53⁄16

ft-in.
3-107⁄8
3-113⁄16
3-107⁄8
3-113⁄16
3-101⁄2
3-1013⁄16

Fig. 6 — Base Unit Dimensions, 48EW,EY038-048
8

CORNER WEIGHT (lb)
1
1021
1080
1033
1094
1068
1129

2
894
934
906
945
953
994

3
1180
1200
1275
1293
1384
1401

4
1347
1388
1455
1496
1550
1592

UNIT
48EJ,EK,EW,EYD024
48EJ,EWE024
48EJ,EK,EW,EYD028
48EJ,EK,EW,EYD030
48EJ,EK,EW,EYD034
48EJ,EWE028
48EJ,EWE030
48EJ,EWE034
48EJ,EK,EW,EYD038
48EJ,EWE038
48EJ,EK,EW,EYD044
48EJ,EWE044
48EJ,EK,EW,EYD048
48EJ,EWE048

WEIGHT
lb
kg
4176 1894
4256 1930

in.

87.68

2227

in.
72.4
73.3

mm
1839
1862

in.
42.4
42.7

mm
1072
1085

69.6

1768

44.0

1118

4262

1933

4342

1969

70.1

1781

44.3

1125

4442
4602
4668
4828
4955
5115

2015
2087
2117
2190
2248
2320

92.7
94.1
89.3
90.8
87.7
89.2

2355
2390
2268
2306
2228
2266

46.9
47.2
46.9
47.2
46.5
46.8

1191
1199
1191
1199
1181
1189

150

3810

NOTICE TO RIGGERS:
ALL PANELS MUST BE IN PLACE
WHEN RIGGING.
NOTE: Rig with four cables and spread with two
92 in. (2337 mm) spreader bars. Maintain a distance of 74 in. (1880 mm) from top of unit to
eyehook.
NOTE:
Add 32 lb
Add 312 lb
Add 346 lb
Add 250 lb
Add 220 lb
Add 285 lb
Add 380 lb

(14.5 kg) for domestic crating.
(142 kg) for export crating (024-034 units).
(157 kg) for export crating (038-048 units).
(113 kg) for power exhaust.
(100 kg) for copper condenser coil (024-034 units).
(129 kg) for copper condenser coil (038,044 units).
(172 kg) for copper condenser coil (048 unit).

Fig. 7 — Rigging Label

Table 1 — Physical Data
UNIT 48EJ,EK,EW,EY
NOMINAL CAPACITY (tons)
OPERATING WEIGHT (lb)*
Unit
Al/Al† (Lo Heat/Hi Heat)
Al/Cu† (Lo Heat/Hi Heat)
Roof Curb (14-in. curb)
COMPRESSOR
Type Ckt 1
Ckt 2
Number of Refrigerant Circuits
Oil (oz) (Ckt 1, Ckt 2)
REFRIGERANT TYPE
Operating Charge (lb-oz)
Circuit 1**
Circuit 2
CONDENSER COIL
Quantity
Rows...Fins/in.
Total Face Area (sq ft)
CONDENSER FAN
Nominal Cfm
Quantity...Diameter (in.)
Motor Hp (1075 Rpm)
EVAPORATOR COIL
Rows...Fins/in.
Total Face Area (sq ft)
EVAPORATOR FAN
Quantity...Size (in.)
Type Drive
Nominal Cfm
Motor Hp
Motor Frame Size (Standard)
(High Efficiency)
Motor Bearing Type
Maximum Allowable Rpm
Motor Pulley Pitch Diameter
Nominal Motor Shaft Diameter (in.)
Fan Pulley Pitch Diameter (in.)
Nominal Fan Shaft Diameter (in.)
Belt, Quantity...Type
Belt, Length (in.)
Pulley Center Line Distance (in.)
Factory Speed Setting (rpm)
FURNACE SECTION
Rollout Switch Cutout Temp (F)|
Burner Orifice Diameter
(in. ...drill size)
Natural Gas
Std
Liquid Propane
Alt
Thermostat Heat Anticipator
Setting (amps)
Stage 1
Stage 2
Gas Input (Btuh)
Stage 1 Low
High
Stage 2 Low
High
Efficiency (Steady State) (%)
Temperature Rise Range
Manifold Pressure (in. wg)
Natural Gas
Std
Liquid Propane
Alt
Gas Valve Quantity
Field Gas Connection Size
(in.-FPT)
HIGH-PRESSURE SWITCH (psig)
Cutout
Reset (Auto.)
LOW-PRESSURE SWITCH (psig)
Cutout
Reset (Auto.)
OUTDOOR-AIR FILTERS
Quantity...Size (in.)
RETURN-AIR FILTERS
Quantity...Size (in.)
POWER EXHAUST
Motor, Quantity...Hp
Fan, Diameter... Width (in.)

024D/E
20

028D/E
25

030D/E
27

034D/E
30

4176/4256
4396/4476
365

4262/4342
4482/4562
365

06D328
06D818
2
115, 88

06D328
06D328
2
115 ea.

06D537
06D328
2
115 ea.

06D537
06D537
2
115 ea.

R-22
25-0
31-0

25-0
25-0
25-0
25-0
25-0
25-0
3
Cross-Hatched ⁄89 Copper Tubes, Aluminum Lanced, Aluminum Pre-Coated, or Copper Plate Fins
1
1
1
1
4...15
4...15
4...15
4...15
33.3
33.3
33.3
33.3
Propeller Type
13,420
13,420
13,420
13,420
2...30
2...30
2...30
2...30
1
1
1
1
Cross-Hatched 3⁄89 Copper Tubes, Aluminum Plate Fins, Intertwined Circuits
4...15
4...15
4...15
4...15
31.7
31.7
31.7
31.7
Centrifugal Type
2...20x15
2...20x15
2...20x15
2...20x15
Belt
Belt
Belt
Belt
8,000
10,000
11,000
12,000
5
10††
15
7.5
10††
15
10
15††
20
10
15††
20
S184T
S215T
D254T
S213T
S215T
D254T
S215T
D254T
S256T
S215T
D254T
S256T
S184T
S215T
S254T
S213T
S215T
S254T
S215T
S254T
S256T
S215T
S254T
S256T
Ball
Ball
Ball
Ball
1200
1200
1200
1200
4.8
4.4
5.7
5.4
6.1
5.5
4.4
4.9
5.9
4.4
5.7
5.9
13⁄8
1 5 ⁄8
13⁄8
13⁄8
1 5 ⁄8
13⁄8
1 5 ⁄8
15⁄8
13⁄8
15⁄8
15⁄8
11⁄8
12.4
8.6
9.1
12.4
11.1
8.7
9.4
8.1
8.7
9.0
9.1
8.7
115⁄16
115⁄16
115⁄16
115⁄16
1...BX59 2...BX51 2...5VX530 1...BX59 1...5VX590 2...5VX530 2...BX52 2...5VX500 2...5VX530 2...BX51 2...5VX530 2...5VX530
62
54
53
62
59
53
55
50
53
54
53
53
16.0-18.7 15.6-18.4 15.0-17.9
15.6-18.4
15.0-17.9 15.6-18.4
15.0-17.9
15.6-18.4
15.0-17.9
717
924
1096
773
962
1106
848
1059
1187
884
1096
1187
225

225

.111...34
.089...43

0.1
0.1
262,500
394,000
350,000
525,000
82
15-45/35-65

3.5
3.5
2
1.5

426
320

7
22

8...16 × 25
4...20 × 25
10...20x24x2
4...1
11...10

10...20x24x2
10...20x24x2
10...20x24x2
Direct Drive, 3-Speed, Single-Phase Motor (Factory-Wired for High Speed) and Forward-Curved Fan
4...1
4...1
4...1
11...10
11...10
11...10
NOTE: High heat is for 48EJ,EW only.

LEGEND
Al — Aluminum
Cu — Copper

VFD
(Hp)

*Weight of unit does not include variable frequency drive (VFD) barometric relief, or power
exhaust. If a VFD is installed, add the VFD weight in the table at right.
†Evaporator coil fin material/condenser coil fin material.
**Sizes 024-034: Circuit 1 uses the lower portion of condenser coil, Circuit 2 uses the upper
portion. Sizes 038-048: Circuit 1 uses the left condenser coil, Circuit 2 the right. All units
have intertwined evaporator coils.
††Motor and drive shown will deliver approximately 2.5 in. wg net external static. See
Table 2 for more information.
\Rollout switch is manual reset.

5
7.5
10
15
20

208/230 v
20
51
51
61
63

25
30

105
172

VFD WEIGHTS (lb)
460 v
22
37
61
63
111
112
118

575 v
60
64
64
109
109
174
180

Table 1 — Physical Data (cont)
UNIT 48EJ,EK,EW,EY
NOMINAL CAPACITY (tons)
OPERATING WEIGHT (lb)*
Unit
Al/Al† (Lo Heat/Hi Heat)
Al/Cu† (Lo Heat/Hi Heat)
Roof Curb (14-in. curb)
COMPRESSOR
Type Ckt 1
Ckt 2
Number of Refrigerant Circuits
Oil (oz) (Ckt 1, Ckt 2)
REFRIGERANT TYPE
Operating Charge (lb-oz)
Circuit 1**
Circuit 2
CONDENSER COIL
Quantity
Rows...Fins/in.
Total Face Area (sq ft)
CONDENSER FAN
Nominal Cfm
Quantity...Diameter (in.)
Motor Hp (1075 Rpm)
EVAPORATOR COIL
Rows...Fins/in.
Total Face Area (sq ft)
EVAPORATOR FAN
Quantity...Size (in.)
Type Drive
Nominal Cfm
Motor Hp
Motor Frame Size (Standard)
(High Efficiency)
Motor Bearing Type
Maximum Allowable Rpm
Motor Pulley Pitch Diameter
Nominal Motor Shaft Diameter (in.)
Fan Pulley Pitch Diameter (in.)
Nominal Fan Shaft Diameter (in.)
Belt, Quantity...Type
Belt, Length (in.)
Pulley Center Line Distance (in.)
Factory Speed Setting (rpm)
FURNACE SECTION
Rollout Switch Cutout Temp (F)|
Burner Orifice Diameter
(in. ...drill size)
Natural Gas
Std
Liquid Propane
Alt
Thermostat Heat Anticipator
Setting (amps)
Stage 1
Stage 2
Gas Input (Btuh)
Stage 1 Low
High
Stage 2 Low
High
Efficiency (Steady State) (%)
Temperature Rise Range
Manifold Pressure (in. wg)
Natural Gas
Std
Liquid Propane
Alt
Gas Valve Quantity
Field Gas Connection Size (in.-FPT)
HIGH-PRESSURE SWITCH (psig)
Cutout
Reset (Auto.)
LOW-PRESSURE SWITCH (psig)
Cutout
Reset (Auto.)
OUTDOOR-AIR FILTERS
Quantity...Size (in.)
RETURN-AIR FILTERS
Quantity...Size (in.)
POWER EXHAUST
Motor, Quantity...Hp
Fan, Diameter... Width (in.)

10
S215T
S215T
6.1
13⁄8
13.7
1...5VX650
65
15.6-18.4
779

038D/E
35

044D/E
40

048D/E
45

4442/4602
4727/4887
410

4668/4828
4953/5113
410

4955/5115
5335/5495
410

06D537
06D537
2
115 ea.

06EA250
06EA250
2
224 ea.
R-22

06EA265
06EA250
2
304, 224

34-0
35-0
41-0
34-0
35-0
41-0
3
Cross-Hatched ⁄89 Copper Tubes, Aluminum Lanced, Aluminum Pre-Coated, or Copper Plate Fins
2
2
1
1
3...15
3...15
4...15
3...15
58.3
58.3
66.7
Propeller Type
27,064
27,064
27,064
4...30
4...30
4...30
1
1
1
Cross-Hatched 3⁄89 Copper Tubes, Aluminum Plate Fins, Intertwined Circuits
3...15
3...15
4...15
34.7
34.7
34.7
Centrifugal Type
2...20x15
2...20x15
2...20x15
Belt
Belt
Belt
14,000
16,000
18,000
15††
20
15
20††
25
20
25††
30
D254T
S256T
D254T
S256T
S284T
S256T
S284T
S286T
S254T
S256T
S254T
S256T
S284T
S256T
S284T
S286T
Ball
Ball
Ball
1200
1200
1200
5.3
5.7
5.3
5.7
7.5
6.3
5.9
7.5
15⁄8
1 5 ⁄8
15⁄8
15⁄8
17⁄8
15⁄8
17⁄8
17⁄8
9.5
9.5
9.5
9.5
11.1
11.1
12.5
11.1
115⁄16
115⁄16
115⁄16
2...5VX530
2...5VX550
2...5VX530
2...5VX550
2...5VX590
2...5VX570
2...5VX630
2...5VX610
53
55
53
55
59
57
63
59
15.0-17.9
15.0-17.9
14.6-17.6
15.0-17.9
14.6-17.6
976
1050
976
1050
1182
993
1134
1182
225

225

.120...31
.096...41

0.1
0.1
300,000
600,000
400,000
800,000
82
10-40/30-60

3.5
3.5
2
1.5

426
320

7
22

7
22
8...16 × 25
4...20 × 25

7
22

10...20x24x2
10...20x24x2
10...20x24x2
Direct Drive, 3-Speed, Single-Phase motor (Factory-Wired for High Speed) and Forward Curved Fan
4...1
4...1
4...1
11...10
11...10
11...10
NOTE: High heat is for 48EJ,EW only.

LEGEND
Al —
Cu —

Aluminum
Copper

VFD
(Hp)

VFD WEIGHTS (lb)
460 v
22
37
61
63

5
7.5
10
15

208/230 v
20
51
51
61

575 v
60
64
64
109

20
25

63
105

111
112

109
174

172

118

180

Table 2 — Evaporator Fan Motor Data (Units with Starting Serial Numbers 4197 and Later)
UNIT
SIZE
48E

024

028

030

034

038

044

048

MOTOR
HP

MOTOR
SHAFT
DIA.
(in.)

FAN
SHAFT
SPEED
(rpm)

MOTOR
SHEAVE

5
10
15
7.5
10
15
10
15
20
10
15
20
10
15
20
15
20
25
20
25
30

1.12
1.38
1.62
1.38
1.38
1.62
1.38
1.62
1.62
1.38
1.62
1.62
1.38
1.62
1.62
1.62
1.62
1.88
1.62
1.88
1.88

717
924
1096
773
962
1106
848
1059
1187
884
1096
1187
779
976
1050
976
1050
1182
993
1134
1182

BK55
2BK50
2B5V56
BK60H
1B5V60
2B5V54
2BK50
2B5V48
2B5V58
2BK50
2B5V56
2B5V58
1B5V60
2B5V52
2B5V56
2B5V52
2B5V56
2B5V74
2B5V62
2B5V80
2B5V74

MOTOR
SHEAVE
PITCH
DIAMETER
(in.)
4.8
4.4
5.7
5.4
6.1
5.5
4.4
4.9
5.9
4.4
5.7
5.9
6.1
5.3
5.7
5.3
5.7
7.5
6.3
5.9
7.5

BUSHING
DIAMETER
(in.)

FAN
SHEAVE

None-1.125
None-1.375
B-1.625
H-1.375
H-1.375
B-1.625
None-1.375
B-1.625
B-1.625
H-1.375
B-1.625
B-1.625
None-1.375
B-1.625
B-1.625
B-1.625
B-1.625
B-1.875
B-1.625
B-1.875
B-1.875

1B5V124
2B5V86
2B5V90
1B5V124
1B5V110
2B5V86
2B5V94
2B5V80
2B5V86
2B5V90
2B5V90
2B5V86
1B5V136
2B5V94
2B5V94
2B5V94
2B5V94
2B5V110
2B5V110
2B5V124
2B5V110

FAN
SHEAVE
PITCH
DIAMETER
(in.)
12.4
8.6
9.1
12.4
11.1
8.7
9.4
8.1
8.7
9.0
9.1
8.7
13.7
9.5
9.5
9.5
9.5
11.1
11.1
12.5
11.1

BUSHING
DIAMETER
(in.)

BELT
(QUANTITY)

OUTSIDE
BELT
LENGTH

BELT
TENSION
(Lb at
.24 in.)

B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375
B-1.9375

BX59
(2) BX51
(2) 5VX530
BX59
5VX590
(2) 5VX530
(2) BX52
(2) 5VX500
(2) 5VX530
(2) BX51
(2) 5VX530
(2) 5VX530
5VX650
(2) 5VX530
(2) 5VX550
(2) 5VX530
(2) 5VX550
(2) 5VX590
(2) 5VX570
(2) 5VX630
(2) 5VX590

62
54
53
62
59
53
55
50
53
54
53
53
65
53
55
53
55
59
57
63
59

5.10
5.21
6.00
6.48
7.37
6.12
5.27
6.63
7.31
5.24
6.00
7.31
7.62
6.37
7.60
6.37
7.60
7.60
7.22
7.36
9.07

NOTE: Motor shaft speed is 1750 rpm. The fan shaft diameter is 115⁄16 inches.

Step 4 — Install Flue Hood — Flue hood is shipped
inside gas section of unit. To install, secure flue hood to access panel. See Fig. 10.
NOTE: When properly installed, flue hood will line up with
combustion fan housing. See Fig. 11.

Fig. 8 — Air Distribution — Thru-the-Bottom

Fig. 9 — Air Distribution — Thru-the-Side

Fig. 10 — Flue Hood Location

Step 5 — Trap Condensate Drain — See Fig. 3-6
for drain location. Condensate drain is open to atmosphere
and must be trapped. Install a trapped drain at the drain location. A trap at least 4-in. deep must be used. See Fig. 12.
Trap must be installed to prevent freeze-up.
Condensate pans are sloped so that water will completely
drain from the condensate pan to comply with indoor air quality guidelines. The condensate drain pan is fitted with a 1-in.
FPT coupling.
Step 6 — Install Gas Piping — Unit is equipped for
use with natural gas. Installation must conform with local
building codes or, in the absence of local codes, with the
National Fuel Gas Code, ANSI Z223.1.
Install manual gas shutoff valve with a 1⁄8-in. NPT pressure tap for test gage connection at unit. Field gas piping
must include sediment trap and union. See Fig. 13. An
1⁄8-in. NPT is also located on the gas manifold adjacent to
the gas valve.

Fig. 11 — Combustion Fan Housing Location

Do not pressure test gas supply while connected to unit.
Always disconnect union before servicing.
IMPORTANT: Natural gas pressure at unit gas connection must not be less than 5 in. wg or greater than
13.5 in. wg.
Size gas-supply piping for 0.5-in. wg maximum pressure
drop. Do not use supply pipe smaller than unit gas
connection.

Step 7 — Controls Options — The control options
that the units can provide are based on the following parameters: CV (constant volume) or VAV (variable air volume)
operation; stand-alone unit with field-supplied sensors installed (CV or VAV); as a system via Carrier Comfort System (TEMP or VVTt); optional electronic expansion board
installed (CV or VAV); linked to the Carrier Comfort
Network; and availability of a computer and software
(ComfortWorks™ Building Supervisor, and Service Tool) or
LID-2B accessory installed to access the base control board.
See Table 3.
NOTE: Access to the base control board allows unit occupancy schedules, unit timeclock, and various set points to be
changed from their factory-defined default settings.
All units are equipped with a supply air thermistor (SAT)
located in the supply fan discharge and an outdoor air thermistor (OAT) located in the outdoor air hood. Variable air
volume units are supplied with a return air thermistor (RAT)
located on the return air damper support.
CONSTANT VOLUME APPLICATIONS — The units, as
shipped, are operable as stand-alone units, using either a standard (mechanical or electronic) 2-stage heat, 2-stage cool thermostat, or with an electronic room sensor and a timeclock to
establish unit start and stop times.
With a standard thermostat (programmable is optional),
heating and cooling operation is set by space temperature.
With a space sensor and timeclock, the machine will operate at default values unless they are changed using appropriate input devices. The space sensor senses space temperature and may be equipped with a timed override feature, which
allows unit operation during unoccupied periods.

Fig. 12 — Condensate Drain Trap Piping Details
(Typical Roof Curb or Slab Mount Shown)

Fig. 13 — Field Gas Piping
The space sensors may be used in multiples of 4 or 9 to
achieve space temperature averaging. The use of a space sensor also allows the unit to be turned on and off from a remote signal.
Features with Thermostat Control of Unit
• two-stage heating
• two-stage cooling
• control of unit using Y1, Y2, W1, W2, and G thermostat
inputs
• control of the indoor fan
• outdoor-air temperature/supply-air temperature
monitoring
• control of an outdoor air condenser fan based on outdoorair temperature
13

Table 3 — Controls Options and Configurations (Non-Thermostat Applications)
UNIT CONFIGURATION
CV or VAV Unit with SPT Sensor
CV Unit with SPT Sensor and Remote
Start/Stop Switch
VAV Unit Remote Start/Stop Switch Only
VAV Unit with SPT Sensor and Remote
Start/Stop Switch
CV
NA
RAT
SAT
SPT
VAV

—
—
—
—
—
—

DEFAULT COOLING
Unoccupied Cooling — 90 F (SPT)
Occupied Cooling — NA
Unoccupied Cooling — 90 F (SPT)
Occupied Cooling — 78 F (SPT)
Unoccupied Cooling — 90 F (RAT)
Occupied Cooling — 55 F (SAT)
Unoccupied Cooling — 90 F (SPT)
Occupied Cooling — 55 F (SAT)

LEGEND
Constant Volume
Not Available
Return-Air Temperature
Supply-Air Temperature
Space Temperature
Variable Air Volume

DEFAULT HEATING
Unoccupied Heating — 55 F (SPT)
Occupied Heating — NA
Unoccupied Heating — 55 F (SPT)
Occupied Heating — 68 F (SPT)
Unoccupied Heating — 55 F (RAT)
Occupied Heating — 68 F (RAT)*
Unoccupied Heating — 55 F (SPT)
Occupied Heating — 68 F (RAT)*

*With DIP Switch No. 5 configured to OPEN (Occupied Heat
Enabled).
NOTE: Space temperature sensor and remote start/stop switch are
field-supplied.

• ability to initiate timed override from T-55 or T-56 sensors
for a timed period of 1 to 4 hours
• ability to use multiple space temperature sensors to average the space temperature
• temperature compensated start to calculate early start times
before occupancy
• access to the Display, Maintenance, Configuration,
Service, and Set Point data tables through network
software
When the unit is equipped with a field-supplied space
temperature sensor and a remote contact closure (remote start/
stop) on the base control board, the occupied default set points
will monitor unit operation. The occupied default set points
are 78 F cooling and 68 F heating. See Fig. 14 for remote
start/stop wiring.
NOTE: For units with a field-supplied space temperature sesor which have not had the base unit control board accessed
via software to set an occupancy schedule, the remote start/
stop closure will allow the unit to operate in the preconfigured occupied default set points (based on return-air
temperature) of 78 F cooling and 68 F heating. Without this
feature, the unit will control to the unoccupied default set
points of 90 F cooling and 55 F heating.
An electronic expansion board may be field-installed to
provide the following features:
• control of modulating economizer damper to maintain indoor air quality (IAQ) when outdoor conditions are
suitable
NOTE: The IAQ sensor must be set for current output
(4 to 20 mA), not voltage output. Ensure the jumper on
the sensor is in the upper position. See Fig. 15.
• provide discrete inputs for fan status, filter status, fieldapplied status, and demand limit
• provide an output for the external alarm light indicator
• provide power exhaust fire outputs for direct control of
modulated power exhaust stages during fire or smoke modes
• control of smoke control modes including evacuation, smoke
purge, pressurization, and fire shutdown (modulating power
exhaust required)
When the unit is connected to the CCN (Carrier Comfort
Network), the following expansion board features can be
utilized:
• perform Demand Limit functions based on CCN loadshed
commands or the state of the discrete input
• alarm monitoring of all key parameters
• CCN protocol
• provides CCN IAQ participation
See Carrier TEMP or VVTt (Variable Volume and Temperature) literature for complete TEMP (single zone) or VVT
(multi-zone) application information.

• control of modulating economizer damper to provide free
cooling when outdoor conditions are suitable, using
supply-air temperature as a control point
• control of the economizer damper and indoor fan to obtain
unoccupied free cooling
• provide power exhaust output to an external power exhaust controller
• support a field test for field checkout
• control of 2 stages of CV power exhaust
• compressor Time Guardt (power up, minimum off and on
times)
• compressor lockout during low supply-air temperature
Additional features are provided by accessing the standard unit control board via software with a computer. These
features are:
• electronic expansion board features (if installed)
• control board diagnostics
• ability to change supply air set point (economizer control)
• ability to change high outdoor temperature lockout set point
(economizer control)
• ability to change power exhaust set points
NOTE: A CV unit without a thermostat requires a fieldsupplied sensor for operation.
Features with Sensor Control of Unit (Stand-Alone Applications — Unit control is limited to CV unoccupied default
set points, 90 F for cooling, 55 F for heating. There are
2 sensor options available:
• T-55 sensor will monitor room temperature and provide
unoccupied override capability (1 hour)
• T-56 sensor will monitor room temperature, provide unoccupied override capability (1 hour), and provide a temperature offset of 5° F.
Standard features are:
• support of remote occupied/unoccupied input to start and
stop the unit
• cooling capacity control of 3 stages using economizer and
2 compressors to maintain space temperature to an occupied or unoccupied set point
• enable heating or cooling during unoccupied periods as
required to maintain space temperature within the unoccupied set points
• adjustment of space temperature set points of ±5° F when
using a T-56 sensor
Additional features with sensor control of unit (with computer access) are:
• 365 day timeclock with backup (supports minute, hour, day
of week, date, month, and year)
• daylight savings time function
• occupancy control with 8 periods for unit operation
• holiday table containing up to 18 holiday schedules
14

VARIABLE AIR VOLUME (VAV) APPLICATIONS
Features with Stand-Alone Applications — The units, as
shipped, are operable as stand-alone units with the addition
of a timeclock to establish unit start and stop times.
Heating and cooling in both on and off modes is controlled to default values by the base unit control. Set points
may be changed with appropriate input devices.
The control has an on-board occupancy schedule which
can be set using an input device and eliminates the need for
an external timeclock.
During both the on and off periods, cooling operation is
controlled to the supply air setting and heating is controlled
to the return air setting (or to the optional space temperature
sensor). During the on period, the supply fan runs continuously. During the off period, the supply fan will be activated
if the return air sensor is outside of the set points and will
run log enough to accurately sample the space temperature.
The supply fan will then continue to run until any heating or
cooling load is satisfied, at which point it will turn off.
The use of a space sensor will allow for supply air reset
to conserve energy and maintain comfort. If equipped with
an override feature, the sensor will allow operation during
the off period for a fixed length of time.
Base unit control supports a Heat Interlock Relay (field
supplied) to fully open the VAV terminal devices during heating operation.
Standard features of a VAV unit with a remote start/stop
switch are:
• control board diagnostics
• control of an outdoor condenser fan based upon outdoor
air temperature
• control of modulating economizer to provide free cooling
when outdoor conditions are suitable, using supply-air temperature as a set point
• support of remote occupied/unoccupied input to start or
stop the unit
• provide power exhaust output to an external power exhaust controller
• support supply-air temperature reset to offset supply air
set point
• support a field test for field check out
• support linkage to DAV systems
• cooling capacity control of up to 6 stages plus economizer
with compressors and unloaders to maintain supply air temperature set point during occupied periods
• control of one stage of heat to maintain return-air temperature at heating set point during occupied periods
• provide a variable frequency drive high voltage relay output to enable VFD
• control of heat interlock relay
• compressor Time Guard override (power up, minimum off
and on times)
With the addition of a remote start/stop switch heating or
cooling is enabled during unoccupied periods as required to
maintain space temperature to within unoccupied set points.
Additional features may be provided with Electronic
Access to Unit Control Board. These features are:
• additional control board diagnostics
• electronic expansion board features (if installed)
• control of the economizer damper and indoor fan to obtain
unoccupied free cooling
• 365-day timeclock with backup (supports minute, hour, day,
month, and year)
• holiday table containing up to 18 holiday schedules
• occupancy control with 8 periods for unit operation
• support a set of display, maintenance, configuration, service, and set point data tables for interface with Building
Supervisor, ComfortWorks, or Service Tool software software or accessory LID-2B

REMOTE
START/STOP
SWITCH
(FIELD-SUPPLIED)

R
Y1
Y2
W1
W2
G
C
X

CONTROL
BOX

LEGEND
Field Supplied Wiring

Fig. 14 — Field Control Remote Start/Stop
JUMPER CONNECTION
FOR VOLTAGE OUTPUT

JUMPER CONNECTION
FOR CURRENT OUTPUT

Fig. 15 — Indoor Air Quality Sensor Configuration

Features with Sensor Control of Unit (Network Applications) — The base control board provides, as standard, a connection for use with a Carrier VVT system and can also be
integrated into a Carrier Comfort Network.
When the unit is accessed via a PC equipped with ComfortWorks™, Building Supervisor, or Service Tool software,
or accessory LID-2B, the following features can be
accessed:
• on-board timeclock can be programmed
• occupancy schedules can be programmed
• unit set points can be changed
• alarms can be monitored
This access is available on the base control board via a
RJ-11 phone jack or a 3-wire connection to the communication bus. See Fig. 16. The timeclock has a 10-hour minimum back-up time to provide for unit power off for servicing unit or during unexpected power outages. For complete
Carrier Comfort System (CCS) or Carrier Comfort Network
(CCN) features and benefits, refer to the product literature.
15

When a VAV unit with a space temperature sensor is accessed via a computer, the following additional features are
available:
• ability to initiate timed override from T-55 sensors
• temperature compensated start to calculate early start time
before occupancy
• provide space temperature reset to reset the supply air set
point upward when the temperature falls below the occupied cooling set point
An electronic expansion board may be field-installed to
provide the following features:
• fan status
• filter status
• field-applied status
• demand limiting
• IAQ Sensor
• OAQ Sensor
• alarm light
• fire unit shutdown
• fire pressurization
• fire evacuation
• fire smoke purge
When the unit is connected to the CCN (Carrier Comfort
Network), the following expansion board features can be
utilized:
• CCN IAQ (indoor air quality) participation
• CCN OAQ (outdoor air quality) participation
• CCN demand limit participation
• modulated power exhaust override
• ability to use multiple space temperature sensors (multiples of 4 and 9 only) to average space temperature (DAV
only)
A field-supplied T-55 space temperature sensor can be added
to monitor room temperature and provide unoccupied override capability (1 hour).
When the unit is equipped with a field-supplied space temperature sensor and a remote contact closure (remote start/
stop) the occupied default set points will monitor unit operation. The occupied default set points are 55 F (supply air)
cooling and 68 F (return air temperature) heating. See
Fig. 14 for remote start/stop wiring.
NOTE: For units without a space temperature sensor and which
have not had the base unit control board accessed via software to set an occupancy schedule, the remote start/stop closure will allow the unit to operate in the pre-configured occupied default set points of 55 F (supply-air temperature)
cooling and 68 F (return-air temperature) heating. Without
an occupancy schedule, the unit will control to the unoccupied default set points of 90 F (return air) cooling and 55 F
(return air) heating.
Features with Network Applications — The base control board
provides, as standard, a connection for use with a Carrier
Comfort System and can also be integrated into a Carrier
Comfort Network. When the unit is accessed via a PC equipped
with ComfortWorks™, Building Supervisor, or Service Tool
software or LID-2B accessory, the following features can be
accessed:
• on-board timeclock can be programmed
• occupancy schedules can be programmed
• unit set points can be changed
• alarms can be monitored
This access is available on the base control board via a
RJ-11 phone jack or a 3-wire connection to the communication bus. See Fig. 16. The internal timeclock has a 10-hour
minimum back-up time to provide for unit power off for servicing unit or during unexpected power outages. For complete Carrier Comfort System (CCS) or Carrier Comfort
Network (CCN) features and benefits, refer to the product
literature.

Step 8 — Make Electrical Connections
POWER WIRING — Units are factory wired for the voltage
shown on the unit nameplate.
When installing units, provide a disconnect per NEC
(National Electrical Code) of adequate size (MOCP [maximum overcurrent protection] of unit is on the informative
plate). All field wiring must comply with NEC and all local
codes. Size wire based on MCA (minimum circuit amps) on
the unit informative plate. See Fig. 17 for power wiring connections to the unit power terminal block and equipment ground.
The main power terminal block is suitable for use with
aluminum or copper wire. See Fig. 17. Units have circuit
breakers for compressors, fan motors, and control circuit. If
required by local codes, provide an additional disconnect switch.
Whenever external electrical sources are used, unit must be
electrically grounded in accordance with local codes, or in
absence of local codes, with NEC, ANSI C1-latest year.
All field wiring must comply with NEC and local code
requirements.
FIELD POWER SUPPLY — Unit is factory wired for voltage shown on unit nameplate. See Table 4 for electrical data.
Field wiring can be brought into the unit from bottom
(through basepan and roof curb) or through side of unit (corner post next to control box).
A 31⁄2-in. NPT coupling for field power wiring and a
3⁄4-in. NPT coupling for 24-v control wiring are provided in
basepan. In the side post, there are two 21⁄2-in. (024-034) or
3-in. (038-048) knockouts for the field power wiring. See
Fig. 3-6. If control wiring is to be brought in through the
side of unit, a 7⁄8-in. diameter hole is provided in the condenser side post next to the control box.
If disconnect box is mounted to corner post, be careful
not to drill any screws into the condenser coil.
Routing Through Bottom of Unit — If wiring is brought in
through bottom of unit, use field-supplied watertight conduit
to run power wiring from basepan out through bottom
31⁄2-in. hole to the disconnect box and back into unit to the
main control box.
Use strain relief going into control box through 21⁄2-in.
diameter hole provided. After wires are in unit control box,
connect to power terminal block (see Power Wiring section
above).
Low-voltage wiring must be run in watertight conduit from
the basepan to control box and through 7⁄8-in. diameter hole
provided in bottom of unit control box. Field-supplied strain
relief must be used going into the box. After wiring is in
control box, make connections to proper terminals on terminal blocks (see Field Control Wiring section on page 21).
Install conduit connector in unit basepan as shown in
Fig. 3-6. Route power and ground lines through connector to
terminal connections in unit control box as shown on unit
wiring diagram and Fig. 17.
Routing Through Side of Unit — Route power wiring in fieldsupplied watertight conduit into unit through 21⁄2-in. hole.
See Fig. 17.
Use field-supplied strain relief going into control box through
21⁄2-in. diameter hole provided. After wires are in unit control box, connect to power terminal block (see Power Wiring
section on this page).
Bring low-voltage control wiring through factory-drilled
7⁄8-in. diameter hole in condenser side post. Use strain relief
going into 7⁄8-in. diameter hole in bottom of unit control box.
After wiring is in control box, make connection to proper
terminals on terminal blocks (see Field Control Wiring section on page 21).
16

17
LEGEND
CCN
COM
D
LED
N.C.

—
—
—
—
—

Carrier Comfort Network
Common
Diode
Light-Emitting Diode
Normally Closed

N.O.
R
SIO
SW
T

—
—
—
—
—

Normally Open
Relay
Serial Input/Output
Switch
Terminal

*Where X is the unit control software version number.

Fig. 16 — Control Board Diagram

Table 4 — Electrical Data
COMPRESSOR
VOLTAGE
OFM
IFM
UNIT
NOMNAL
RANGE
No.
1
No. 2
SIZE
VOLTAGE
48E (3 Ph 60 Hz) Min Max RLA LRA RLA LRA Qty Hp FLA Hp FLA
(ea)

024

028

030

187

254

39.1

228

25.6

160

5.3

460

414

508

19.9

114

11.5

2.7

575

518

632

16.0

9.6

2.4

208/230

187

254

39.1

228

39.1

228

5.3

460

414

508

19.9

114

19.9

114

2.7

575

518

632

16.0

2.4

208/230

187

254

57.1

266

39.1

228

5.3

460

414

508

25.6

120

19.9

114

2.7

575

518

632

20.5

16.0

2.4

FLA LRA

16.7/ —
15.2 23.6
—
10 30.8/
28.0 23.6
—
15 46.2/
42.0 23.6
—
5
7.6
12.6
—
10 14.0
12.6
—
15 21.0
12.6
—
5
6.1
12.6
—
10 11.0
12.6
—
15 17.0
12.6
24.2/ —
7.5 22.0
23.6
30.8/ —
10 28.0
23.6
—
46.2/
15 42.0
23.6
—
7.5 11.0
12.6
—
10 14.0
12.6
—
15 21.0
12.6
—
7.5
9.0
12.6
—
10 11.0
12.6
—
15 17.0
12.6
—
10 30.8/
28.0 23.6
—
15 46.2/
42.0 23.6
—
20 59.4/
54.0 23.6
—
10 14.0
12.6
—
15 21.0
12.6
—
20 27.0
12.6
—
10 11.0
12.6
—
15 17.0
12.6
—
20 22.0
12.6
5

208/230

POWER COMBUSTION
EXHAUST FAN MOTOR

—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6

POWER SUPPLY

FLA

MCA

MOCP*

0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50

101.8/100.3
125.4/123.9
115.9/113.1
139.5/136.7
131.3/127.1
154.9/150.7
49.4
62.0
55.8
68.4
62.8
75.4
40.5
53.1
45.4
58.0
51.4
64.0
122.8/120.6
146.4/144.2
129.4/126.6
153.0/150.2
144.8/140.6
168.4/164.2
61.2
73.8
64.2
76.8
71.2
83.8
49.8
62.4
51.8
64.4
57.8
70.4
151.9/149.1
175.5/172.7
167.3/163.1
190.9/186.7
180.5/175.1
204.1/198.7
71.3
83.9
78.3
90.9
84.3
96.9
57.4
70.0
63.4
76.0
68.4
81.0

125/125
150/150
150/150
175/175
150/150
175/175
60
80
70
80
80
90
50
60
60
70
60
80
150/150
175/175
150/150
175/175
175/175
200/200
80
90
80
90
90
100
60
70
60
80
70
80
200/200
225/225
225/225
225/225
225/225
250/250
90
100
100
110
100
110
70
90
80
90
80
100

See Legend and Notes on page 19.

Table 4 — Electrical Data (cont)
COMPRESSOR
VOLTAGE
OFM
IFM
UNIT NOMINAL
RANGE
No.
1
No. 2
SIZE
VOLTAGE
48E (3 Ph 60 Hz) Min Max RLA LRA RLA LRA Qty Hp FLA Hp FLA
(ea)

034

038

208/230

187

254

57.1

266

57.1

266

5.3

460

414

508

25.6

120

25.6

120

2.7

575

518

632

20.5

2.4

208/230

187

254

57.1

266

57.1

266

5.3

460

414

508

25.6

120

25.6

120

2.7

575

518

632

20.5

2.4

LEGEND
FLA
— Full Load Amps
HACR — Heating, Air Conditioning and
Refrigeration
IFM
— Indoor (Evaporator) Fan Motor
LRA
— Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
NEC
— National Electrical Code
OFM
— Outdoor (Condenser) Fan Motor
RLA
— Rated Load Amps
*Fuse or HACR circuit breaker.

POWER COMBUSTION
EXHAUST FAN MOTOR
FLA LRA

—
10 30.8/
28.0 23.6
—
15 46.2/
42.0 23.6
—
20 59.4/
54.0 23.6
—
10 14.0
12.6
—
15 21.0
12.6
—
20 27.0
12.6
—
10 11.0
12.6
—
15 17.0
12.6
—
20 22.0
12.6
30.8/ —
10 28.0
23.6
46.2/ —
15 42.0
23.6
—
59.4/
20 54.0
23.6
—
10 14.0
12.6
—
15 21.0
12.6
—
20 27.0
12.6
—
10 11.0
12.6
—
15 17.0
12.6
—
20 22.0
12.6

—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6

POWER SUPPLY

FLA

MCA

MOCP*

0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50

169.9/167.1
193.5/190.7
185.3/181.1
208.9/204.7
198.5/193.1
222.1/216.7
77.0
89.6
84.0
96.6
90.0
102.6
61.9
74.5
67.9
80.5
72.9
85.5
180.5/177.7
204.1/201.3
195.9/191.7
219.5/215.3
209.1/203.7
232.7/227.3
82.4
95.0
89.4
102.0
95.4
108.0
66.7
79.3
72.7
85.3
77.7
90.3

225/200
250/225
225/225
250/250
250/250
275/250
100
110
100
110
110
125
80
90
80
100
90
100
225/225
250/250
250/225
275/250
250/250
275/275
100
110
110
125
110
125
80
90
90
100
90
110

EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
Average Voltage =
or
=

452 + 464 + 455
3
1371

3
= 457
Determine maximum deviation from average voltage.
(AB) 457 − 452 = 5 v
(BC) 464 − 457 = 7 v
(AC) 457 − 455 = 2 v
Maximum deviation is 7 v.
Determine percent voltage imbalance.
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.

NOTES:
1. In compliance with NEC requirements for multimotor and combination load equipment (refer to NEC Articles 430 and 440), the
overcurrent protective device for the unit shall be fuse or HACR
breaker. Canadian units may be fuse or circuit breaker.
2. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply voltage is greater than 2%. Use the following formula to determine
the percent voltage imbalance.
% Voltage Imbalance
max voltage deviation from average voltage
= 100 x
average voltage

IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact your local electric utility company
immediately.

Table 4 — Electrical Data (cont)
COMPRESSOR
VOLTAGE
OFM
IFM
UNIT NOMINAL
RANGE
No.
1
No. 2
SIZE
VOLTAGE
48E (3 Ph 60 Hz) Min Max RLA LRA RLA LRA Qty Hp FLA Hp FLA
(ea)

044

048

208/230

187

254

69.2

345

69.2

345

5.3

460

414

508

28.8

173

28.8

173

2.7

575

518

632

26.7

120

26.7

120

2.4

208/230

187

254

82.1

446

69.2

345

5.3

460

414

508

42.3

223

28.8

173

2.7

575

518

632

34.6

164

26.7

120

2.4

POWER COMBUSTION
EXHAUST FAN MOTOR
FLA LRA

—
15 46.2/
42.0 23.6
—
20 59.4/
54.0 23.6
—
25 74.8/
68.0 23.6
—
15 21.0
12.6
—
20 27.0
12.6
—
25 34.0
12.6
—
15 17.0
12.6
—
20 22.0
12.6
—
25 27.0
12.6
59.4/ —
20 54.0
23.6
74.8/ —
25 68.0
23.6
—
88.0/
30 80.0
23.6
—
20 27.0
12.6
—
25 34.0
12.6
—
30 40.0
12.6
—
20 22.0
12.6
—
25 27.0
12.6
—
30 32.0
12.6

—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
41.6
—
41.6
—
41.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6
—
23.6

POWER SUPPLY

FLA

MCA

MOCP*

0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.96
0.96
0.96
0.96
0.96
0.96
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50
0.50

223.1/218.9
246.7/242.5
236.3/230.9
259.9/254.5
251.7/244.9
275.3/268.5
96.6
109.2
102.6
115.2
109.6
122.2
86.7
99.3
91.7
104.3
96.7
109.3
252.4/247.0
276.0/270.6
267.8/261.0
291.4/284.6
281.0/273.0
304.6/296.6
119.5
132.1
126.5
139.1
132.5
145.1
101.6
114.2
106.6
119.2
111.6
124.2

275/275
300/300
300/300
300/300
300/300
300/300
125
125
125
125
125
150
110
125
110
125
110
125
300/300
300/300
300/300
300/300
300/300
350/300
150
150
150
175
150
175
125
125
125
150
125
150

EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
452 + 464 + 455
3
1371
=
3
= 457
Determine maximum deviation from average voltage.
(AB) 457 − 452 = 5 v
(BC) 464 − 457 = 7 v
(AC) 457 − 455 = 2 v
Maximum deviation is 7 v.
Average Voltage =

Determine percent voltage imbalance.
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.

% Voltage Imbalance
max voltage deviation from average voltage
= 100 x
average voltage

Sensor Wiring (CV or VAV) — The temperature sensor is
wired into the unit control board. See Fig. 21.
The unit is controlled with a T-55 or T-56 (CV only) zone
sensor. Terminal TH (T-56) or T1 (T-55) on the sensor is
connected to T1 of the base module board. Terminal COM
(T-56) or T2 (T-55) on the sensor is connected to T2 on the
base module board. If a T-56 set point override sensor is used,
the override connection SW on the sensor is connected to T3
on the base module board.
If more than sensor is being used and averaged, sensors
must be wired in multiples of 4 or 9. See Fig. 22.
Heat Interlock Relay — VAV units require a field-supplied
heat interlock relay (HIR) to drive the air terminal wide open
when in heat mode. Heat Interlock relay part number is
HN61KK041.

IMPORTANT: THE VAV (variable air volume) units
use variable frequency drives, which generate, use and
can radiate radio frequency energy. If units are not installed and used in accordance with these instructions,
they may cause radio interference. They have been tested
and found to comply with limits of a Class A computing device as defined by FCC (Federal Communications Commission) regulations, Subpart J of Part 15,
which are designed to provide reasonable protection
against such interference when operated in a commercial environment.

The unit must be electrically grounded in accordance
with local codes and NEC ANSI/NFPA 70 (National Fire
Protection Association).
Affix crankcase heater sticker (located in the installers packet)
to unit disconnect switch.
Voltage to compressor terminals during compressor operation must be within the voltage range indicated on the
unit nameplate. On 3-phase units, phases must be balanced
within 2%. Contact local power company for correction of
improper voltage or phase imbalance. Unit failure due to operation of unit on improper line voltage or with excessive
phase imbalance constitutes abuse and may cause damage to
unit electrical components.
On 208/230-v units, transformer no. 1 is wired for 230-v.
If 208/230-v unit is to be run with 208-v power supply, the
transformer must be rewired as follows:
1. Remove cap from red (208 v) wire.
2. Remove cap from spliced orange (230 v) wire. Disconnect orange wire from black unit power wire.
3. Cap orange wire.
4. Splice red wire and black unit power wire. Cap wires.

LEGEND
GND — Ground
NEC — National Electrical Code
TB
— Terminal Block
NOTE: Maximum wire size for TB1 is 500 MCM.

Fig. 17 — Field Power Wiring Connections

IMPORTANT: BE CERTAIN UNUSED WIRES
ARE CAPPED. Failure to do so may damage the
transformers.
FIELD CONTROL WIRING — The unit can use either a
Carrier-approved thermostat or a CCN (Carrier Comfort
Network) compatible temperature sensor. Thermostats are used
on CV (constant volume) units only. Control box diagrams
are shown in Fig. 18 and 19.
Thermostat Wiring (CV Only) — Install a Carrier-approved
accessory thermostat assembly (per current price pages) according to the installation instructions included with the accessory or these instructions. Locate the thermostat on a solid
interior wall in the conditioned space to sense the average
temperature.
Route the thermostat cable or equivalent single leads of
colored wire from the subbase terminals to the low-voltage
connection as shown on unit label wiring diagram and in
Fig. 20.
NOTE: For wire runs up to 50 ft, use no. 18 AWG
(American Wire Gage) insulated wire (35 C minimum). For
50 to 75 ft, use no. 16 AWG insulated wire (35 C minimum).
For over 75 ft, use no. 14 AWG insulated wire (35 C minimum). All wire larger than no. 18 AWG cannot be directly
connected at the thermostat and will require a junction box
and splice at the thermostat.
Set heat anticipators to 0.1 for all voltages.

LEGEND
C
CB
DIP
FU
HR

—
—
—
—
—

Compressor/Contactor
Circuit Breaker
Dual In-Line Package
Fuse
Heater Relay

IF
OF
PEC
TB
TRAN

—
—
—
—
—

Indoor Fan
Outdoor Fan
Power Exhaust Controller
Terminal Block
Transformer

Fig. 18 — Control Box Diagram (Sizes 024-034)

LEGEND
C
CB
DIP
FU
HR

—
—
—
—
—

Contactor/Compressor
Circuit Breaker
Dual In-Line Package
Fuse
Heater Relay

IF
OF
PEC
TB
TRAN

—
—
—
—
—

Indoor Fan
Outdoor Fan
Power Exhaust Controller
Terminal Block
Transformer

Fig. 19 — Control Box Diagram (Sizes 038-048)

NOTE: Sensor part numbers are as follows:
T-55 — CEC0121448-01
T-56 — CEC0121503-01

Fig. 21 — Field Control Temperature Sensor Wiring
(CV or VAV Units)
Fig. 20 — Field Control Thermostat Wiring

SPACE TEMPERATURE AVERAGING — 4 SENSOR APPLICATION

SPACE TEMPERATURE AVERAGING — 9 SENSOR APPLICATION

Fig. 22 — Space Temperature Averaging Wiring
signal pins must be wired to signal ground pins. Wiring connections for CCN should be made at the 3-pin plug (CCN
located at the base board). Consult CCN literature for further information.
Conductors and drain wire must be 20 AWG minimum
stranded, tinned copper. Individual conductors must be insulated with PVC, PVC/nylon, vinyl, Teflon, or polyethylene. An aluminum/polyester 100% foil shield and an outer
jacket of PVC, PVC/nylon, chrome vinyl, or Teflon with a
minimum operating temperature range of −20 C to 60 C
(−4 F to 140 F) is required. Table 5 lists cables that meet the
requirements.

Remote Field Control — A switch closure across terminals
R and W1 on TB-3 will initiate the Occupied mode. This
can be done manually as well as through a field-supplied
timeclock.
Service Tool, Building Supervisor, and ComfortWorks™
Software — Access to the control board can be achieved through
the terminal marked CCN via a 3-wire bus.
IMPORTANT: The default bus address is 0. The default element number is 1. Refer to CCN literature to
change the default values, if needed.
Carrier Comfort Network Interface — The 48E units can be
connected to the CCN. The communication bus wiring is supplied and installed in the field. Wiring consists of shielded,
3-conductor cable with drain wire.
The system elements are connected to the communication
bus in a daisy chain arrangement. The positive pin of each
system element communication connector must be wired to
the positive pins of the system element on either side of it,
the negative pins must be wired to the negative pins, and the

Table 5 — CCN Connection Approved Shielded Cables
MANUFACTURER
Alpha
American
Belden
Columbia

CABLE PART NO.
2413 or 5463
A22503
8772
02525

2. Assemble hood sides, top, and cross member with gasketed screws provided. See Fig. 24.
3. Attach 10 green speed clips (provided) to hood top.
4. Apply black seal strip (provided) to mounting flanges of
hood sides being sure to cover mounting holes. See
Fig. 25.
NOTE: Each hood assembly has a slotted side that should
be adjacent to the other hood when mounted to the unit.
5. Apply black seal strip (provided) to hood top mounting
flange. Seal strip of hood top mounting flange must press
tightly against seal strip of hood side mounting flanges.
See Fig. 26.
6. Add gray foam strip (provided in package) to cross members on bottom tray. See Fig. 27.
7. Place gray foam strip (provided) on inside of slotted hood
side between filter and cross member opposite the mounting end. See Fig. 28.
8. Attach gray foam strip (provided) to block-off baffle on
outer face of flange. See Fig. 29.
9. Remove the screws on each end and along top of damper
assembly of unit. Remove top 2 screws on each side of
filter panel under damper assembly. Set hood assembly
in place and attach to unit using these screws.
10. Attach accessory enthalpy bracket on hood side furthest
from control box end. Locate bracket on inside upper
right-hand corner of economizer hood using hood mounting holes. Mount outdoor-air thermistor to enthalpy bracket
(if purchased). Attach and wire enthalpy assembly. Place
quick connects on enthalpy wires.
11. Remove screws along bottom of damper assembly. Locate and mount blockoff baffle using these screws.
12. Assemble 2 filter tracks side-by-side with the assembled ends together.
13. Attach mounting angle (without tabs) to the assembled
end of the filter track. See Fig. 30.
14. Attach 6 green speed clips (provided) to mounting angles.
Engagement section of clip faces inside of rack.
15. Attach remaining mounting angle (with tabs) to other
end of the filter track with no. 10 screws provided. See
Fig. 31.
16. Place filter track assembly in bottom of hood by placing
tabbed end into slotted side (with tab on bottom) and
attaching opposite end to hood with speed clips and gasketed screws provided. Tabs can be hand bent after they
have been inserted into the side.
NOTE: The filter track assembly end with screws should
face away from the other hood when mounted on the
unit.
NOTE: Tabs from both filter tracks will be in the same
space. After one filter track has been inserted into hood
side, bend the tabs so they will not interfere with installation of the second hood.
17. Attach black seal strip (provided) to filter cover. Seal
strip should be applied to the center of the large flange
making sure to cover holes. See Fig. 32.
18. Slide two 20 x 25-in. filters into cross members of hood
assembly. Attach filter cover over filters with screws and
speed clips provided.
Minimum Damper Position Setting — Setting of the outdoor air damper position is performed in conjunction with a
shortened version of the field run test. This is performed by
first opening DIP (Dual In-line Package) switch no. 4 then
no. 6. See Fig. 18 and 19 and Direct Digital Controls DIP
Switch Configuration section on page 33.

IMPORTANT: When connecting the CCN communication bus to a system element, use a color coding system for the entire network to simplify installation and
checkout. See Table 6.

Table 6 — Color Code Recommendations
SIGNAL
TYPE
Positive (+)
Ground
Negative (−)

CCN BUS CONDUCTOR
INSULATION COLOR
RED
WHITE
BLACK

CCN PLUG
PIN NO.
1
2
3

NOTE: If a cable with a different color scheme is selected,
a similar color code should be adopted for the entire
network.
At each system element, the shields of the communication bus cables must be tied together. If the communication
bus is entirely within one building, the resulting continuous
shield must be connected to a ground at one point only. If
the communication bus cable exits from one building and
enters another, the shields must be connected to grounds at
the lightning suppressor in each building where the cable
enters or exits the building (one point per building only).
To connect the unit to the network:
1. Turn off power to the control box.
2. Cut the CCN wire and strip the ends of the red (+), white
(ground), and black (−) conductors. (If a different network color scheme is used, substitute appropriate
colors.)
3. Remove the 3-pin male plug from the base module in the
main control box, and connect the wires as follows:
a. Insert and secure the red (+) wire to terminal 1 of the
3-pin plug.
b. Insert and secure the white (ground) wire to
terminal 2 of the 3-pin plug.
c. Insert and secure the black (−) wire to terminal 3 of
the 3-pin plug.
4. Insert the plug into the existing 3-pin mating connector
on the base module in the main control box.

Step 9 — Make Outdoor-Air Inlet Adjustments
ECONOMIZER
NOTE: If accessory power exhaust or barometric relief packages are being added to the unit, install power exhaust or
barometric relief before installing economizer hoods.
Economizer Hood Assembly — The economizer hood is
shipped in a package secured to the outside of the unit and
must be field-assembled. There are 2 hoods on every unit.
The 48EW/EY units are side supply and side return. The return duct limits access to economizer filters from below.
Filter tracks (mounting angle without tabs) must be installed
correctly to allow access to economizer filters from each side.
Perform the following procedure to assemble the economizer hood:
NOTE: Before assembly of the economizer hood, check along
the outer edges of the economizer assembly for any seal strip
protruding past the flanges. Trim the excess seal strip so that
it is flush with the economizer assembly flanges.
1. Apply black seal strip (provided in package) to outside
top-edge of hood sides. Wrap seal strip over edge to cover
top flange (4 hood sides). Make sure seal strip covers
screw holes. Allow strip to overhang 1⁄8-in. past the end
opposite the mounting flange. See Fig. 23.

TOP
FLANGE
BLACK
SEAL
STRIP

HOOD SIDE

MOUNTING
FLANGE

HOOD SIDE

Fig. 23 — Adding Seal Strip to Top of Hood Sides
Fig. 25 — Adding Seal Strip to Mounting Flange of
Hood Sides
HOOD TOP

HOOD SIDE

Fig. 26 — Adding Seal Strip to Hood Top
Mounting Flange
NOTE: Left side economizer hood has mounting angle without tabs
and filter track assembled end on the opposite side.

GRAY FOAM STRIP

Fig. 24 — Economizer Hood Assembly
(Right Side Economizer Hood Shown)
CROSS MEMBER

Fig. 27 — Adding Foam Strip to Cross Member

The outdoor-air damper closes. The control allows 90 seconds for the damper to close in case it is in the full open
position. Next, the indoor-fan contactor will energize. The
outdoor-air damper will remain at 0% for 30 seconds. It will
then move to the 10% position for another 30 seconds. This
will be repeated at every 10% increment for 30 seconds until
the damper reaches 100% open. Close DIP switch no. 4 during the 30 seconds immediately after the desired outdoor air
minimum damper position. The 30-second time period is to
allow time where DIP switch no. 4 can be closed. The default value of the minimum outdoor air damper position is
20%. If the desired minimum position is 30%, allows the
damper position to go to 10% for 30 seconds, then 20% for
30 seconds, and when it reaches 30% close DIP switch
no. 4 during the 30-second period following the 30%
position.
The minimum outdoor air damper position is now set. Close
DIP switch no. 6.

HOOD SIDE
(SLOTTED)
HOOD
TOP

ECONOMIZER SETTINGS
Accessory Enthalpy Control (Fig. 33) — The control
(HH57AC077) is mounted in the economizer hood. See
Fig. 24. The enthalpy setting adjustment is on the enthalpy
control. For maximum benefit of outdoor air, set enthalpy
control to A. See Fig. 34 and 35.
Enthalpy Control Installation — The outdoor air enthalpy control is installed on the inside panel of the outdoor air hood.
The enthalpy control should be mounted when the outdoor
air hoods are assembled. To install the control, perform the
following procedure:
1. Turn off all power. Ensure disconnect is locked out.
2. Remove the economizer inlet filters from the bottom of
the right hand economizer hood. See Fig. 24. See Fig. 36
for economizer details.
3. Mount the outdoor air enthalpy sensor inside the right economizer hood on the right side panel of the hood, adjacent
to the outdoor-air thermistor.
4. Locate the red, violet, and brown wires near the outdoor
air thermistor. Remove the splice from the red and violet
wires. Remove the cap from the brown wire.
5. Install a 1⁄4-in. push on terminal (field-supplied) on the
violet and brown wires.
6. Connect a 1⁄4-in. push on terminal (field provided) to one
end of a 18-gage, 6-in. jumper wire (field-provided). Connect the other end to the red wire and attach a 1⁄4-in. push
on connector (field provided).
7. Connect the red wire with the jumper to terminal TR1.
Connect the jumper to terminal 2. Connect the brown wire
to terminal TR. Connect the violet wire to terminal 3. All
connections are on the enthalpy control.
8. Replace the economizer filters.
9. Return power to unit.

Fig. 28 — Adding Foam Strip to Hood Side

BLOCKOFF BAFFLE

GRAY FOAM STRIP

Fig. 29 — Adding Foam Strip to Blockoff Baffle
MOUNTING ANGLE
(WITHOUT TABS)

FILTER TRACK
ASSEMBLY

Accessory Differential Enthalpy Control (Fig. 33) — The
control (HH57AC077), in conjunction with the accessory enthalpy sensor (HH57AC078), controls economizer operation according to the differential enthalpy. The control is
mounted in the economizer hood. The sensor is mounted in
the return duct (48EJ/EK) or return air plenum (48EW/EY).
Fig. 30 — Mounting Angle (Without Tabs) Attached
to Filter Track Assembly

5. Turn the enthalpy control set point potentiometer clockwise past the ‘‘D’’ setting on the enthalpy control to configure the control to operate on differential enthalpy. See
Fig. 34.
6. Remove the return-air enthalpy sensor from the accessory package. Using the screws provided, mount the sensor inside the return duct near the unit. Do not locate the
control too far from the unit, or the wires will not reach
from the sensor to the control. On 48EW/EY units, the
enthalpy sensor can be installed in the return air section
of the unit, under the return air dampers.
7. Route the wires from the enthalpy sensor to the return
air enthalpy control through the holes on the inside of
the hinged filter access panel. The holes are blocked by
plug buttons which should be removed.
8. Use field-supplied wire ties to attach the violet wire to
the + terminal and the blue wire to the SR terminal.
9. Replace economizer filters.
10. Return power to unit.

MOUNTING ANGLE
(WITH TABS)

Disable Economizer — For applications where the economizer will not be used (areas of high humidity), the economizer should be disabled. To disable the economizer, perform
the following:
1. Turn of power. Lock out disconnect.
2. Locate the OAT (Outdoor Air Thermostat) in the right
hand outdoor air damper area.
3. Locate the splice connecting the violet wire coming from
T24 on the base module board to the red wire coming
from T29 on the base module board. Remove the wire
nut and break the red to violet wire splice.
4. Cap off both wires. When the connection is broken the
base module is fooled into thinking that the enthalpy is
not acceptable and economizer operation is disabled.

Fig. 31 — Mounting Angle (With Tabs) Attached to
Filter Track Assembly

BLACK SEAL STRIP
(CENTERED)

HH57AC077
ENTHALPY CONTROL

FILTER COVER

Fig. 32 — Attaching Seal Strip to Filter Cover
Differential Enthalpy Sensor Installation — To install the control, perform the following procedure:
1. Turn off all power. Ensure disconnect is locked out.
2. Remove the economizer inlet filters from the bottom of
the right hand economizer hood. See Fig. 24.
3. Remove the factory-installed, 620-ohm jumper between
terminals SR and + on the enthalpy control located inside the outdoor air hood.
4. Connect the violet wire from the enthalpy sensor kit to
the + terminal on the enthalpy control. Connect the blue
wire from the enthalpy sensor kit to the SR terminal on
the enthalpy control.

C7400

A1004

HH57AC078
ENTHALPY SENSOR
(USED WITH ENTHALPY
CONTROL FOR DIFFERENTIAL
ENTHALPY OPERATION)

Fig. 33 — Differential Enthalpy Control and Sensor

CONTROL
CURVE
A
B
C
D

CONTROL POINT
(APPROX. DEG.)
AT 50% RH
73 (23)
70 (21)
67 (19)
63 (17)

NOTE: Switches shown in high enthalpy state. Terminals 2 and 3 close
on enthalpy decrease.

Fig. 34 — Wiring Connections for Solid-State
Enthalpy Control (HH57AC077)

RH — Relative Humidity

Fig. 35 — Psychrometric Chart for
Enthalpy Control

NOTE: Partitions shown indicate both side supply (EW/EY) and vertical supply (EJ/EK) units.

Fig. 36 — Economizer Details
28

See Fig. 38. A section of field-supplied 1⁄4-in. plastic tubing
must be run from the high pressure tap on the differential
pressure switch and connected to a field-supplied tap in the
supply-air duct. The tap is usually located 2⁄3 of the way out
on the main supply duct. Remove plug button in panel to
route tubing.
The low pressure tap is factory-routed to the atmosphere. For a positive-pressure building, route the high tap
to building air and low tap to atmosphere. For a negativepressure building, route the high tap to atmosphere and the
low tap to building air.
VAV BUILDING PRESSURE TRANSDUCER — The VAV
building pressure transducer (modulating power exhaust pressure transducer) is located behind the filter access door on
the lower inner panel. See Fig. 38. A section of fieldsupplied 1⁄4-in. plastic tubing must be run from the high pressure tap on the differential pressure switch to the conditioned
space. The pressure tube must be terminated in the conditioned space where a constant pressure is required. This location is usually in an entrance lobby so that the building
exterior doors will open and close properly. Remove plug
button in panel to route tubing.
The low pressure tap is factory-routed to the atmosphere. For a positive-pressure building, route the high tap
to building air and low tap to atmosphere. For a negativepressure building, route the high tap to atmosphere and the
low tap to building air.

Step 10 — Position Power Exhaust/Barometric
Relief Damper Hood — All electrical connections have
been made and adjusted at the factory. The power exhaust
blowers and barometric relief dampers are shipped assembled and tilted back into the unit for shipping. Brackets
and extra screws are shipped in shrink wrap around the dampers. If ordered, each unit will have 4 power exhaust blowers
and motors or 4 barometric relief dampers.
1. Remove 9 screws holding each damper assembly in place.
See Fig. 37. Each damper assembly is secured with 3 screws
on each side and 3 screws along the bottom. Save screws.

Be careful when tilting blower assembly. Hoods and blowers are heavy and can cause injury if dropped.
2. Pivot each damper assembly outward until edges of damper
assembly rest against inside wall of unit.
3. Secure each damper assembly to unit with 6 screws across
top (3 screws provided) and bottom (3 screws from
Step 1) of damper.
4. With screws saved from Step 1, install brackets on each
side of damper assembly.
5. Remove tape from damper blades.
VAV DUCT PRESSURE TRANSDUCER — The VAV duct
pressure transducer (VAV inverter pressure transducer) is located behind the filter access door on the lower inner panel.

NOTES:
1. Unless otherwise specified, all dimensions are to outside of part.
2. Dimensions are in inches.
3. On 48EW,EY units, accessory barometric relief or power exhaust must be mounted in the field-supplied return ductwork.

Fig. 37 — Barometric Relief Damper and Power
Exhaust Mounting Details
29

When replacing the OFM, reconnect the black, yellow, and
blue wires form the outdoor fan contactor to the black, yellow, and blue wires of the Motormaster III control. Run new
wires from the red, orange, and brown wires to the leads of
the new OFM. Connect the green wire from the control to
ground.
NOTE: On all 575-v units, 2 transformers (part no.
HT01AH851) must be used for each Motormaster III control to lower the supply voltage to the control to 460-v. Transformers can be mounted anywhere outside the control box.

Step 11 — Install All Accessories — After all the
factory-installed options have been adjusted, install all fieldinstalled accessories. Refer to the accessory installation instructions included with each accessory.
MOTORMASTERt III INSTALLATION
Install Field-Fabricated Wind Baffles — Wind baffles must
be field-fabricated for all units to ensure proper cooling cycle
operation at low-ambient temperatures. See Fig. 39 for baffle
details. Use 20-gage, galvanized sheet metal, or similar
corrosion-resistant metal for baffles. Use field-supplied screws
to attach baffles to unit. Screws should be 1⁄4-in. diameter
and 5⁄8-in. long. Holes for wind baffles are pre-punched in
the unit sheet metal.

To avoid damage to the refrigerant coils and electrical
components, use recommended screw sizes only.
On 48EJ,EK,EW,EY024-034 units, the wind baffles attach to flanges formed on the outer sheet metal of the unit
where the condenser coil tube sheets attach.
On 48EJ,EK,EW,EY038-048 units, the wind baffles attach to flanges formed on the outer sheet metal of the unit
corner post. The other end of the baffle is attached to the
center panel between the condenser coil and the indoor section. Two baffles are required for 48EJ,EK,EW,EY038-048
units.
Install Motormaster III Controls — Only one Motormaster
III control is required per unit.
Motor — The circuit no. 1 (lead compressor) outdoor-fan
motor (OFM) will need to be changed out in the field to accommodate the Motormaster III accessory. The replacement
motor part no. is HD52AK652.
On 48EJ,EK,EW,EY038-048 units, only one OFM will need
to be changed out. The no. 1 compressor is located at the left
side of the unit looking from the compressor end. The circuit
no. 2 OFMs are controlled to shut off at 55 F and turn on at
65 F outdoor-air temperature.
Sensor — Install the sensor for thermistor input control in
the location shown in Fig. 40A-C. Connect sensor leads to
the violet and gray control signal leads on the Motormaster
III control.
Signal Selection Switch — Remove the cover of the Motormaster III control. Set the switch to accept the thermistor
sensor input signal. Set the frequency to match the unit power
supply (60 Hz).
Motormaster III Control — The recommended mounting location is in the indoor fan section, mounted on the panel that
separates the indoor and outdoor sections. On VAV units,
this location is next to the VFD.
Do not route the Motormaster III wiring next to the VFD
on VAV units. Use a separate connector through the partition
when wiring to the OFM.

VAV — Variable Air Volume

Fig. 38 — Pressure Transducer Locations

BOTH SIDES

77.7
0.312 DIA
HOLES

61
17.167
BETWEEN
HOLES
(TYPICAL)

Electrical Connections

4.62

CROSS-BREAK
78.7

0.5

NOTE: All dimensions are in inches. Material: 20 gage galvanized
steel or other non-corrosive material.

To avoid possibility of electrical shock and personal injury, turn off all power to unit before making electrical
connections.

Fig. 39 — Motormaster III Baffle Details

Fig. 40A — Motormaster III Sensor Location
(Sizes 024-034)
Fig. 40C — Motormaster III Sensor Location
(Size 048)

Internal Wiring — Check all electrical connections in
unit control boxes; tighten as required.

Refrigerant Service Ports — Each refrigerant system has one suction port located in the top of the compressor
motor casing. All units also have one service port on the liquid line valve and one on the compressor discharge valve.
Be sure that caps on the ports are tight.

Crankcase Heaters — Crankcase heaters are energized as long as there is power to the unit, except when the
compressors are operating.
IMPORTANT: Unit power must be on for 24 hours
prior to start-up. Otherwise, damage to compressor may
result.

Variable Frequency Drive (VFD) — The variable
frequency drives are factory set. These settings include factoryinstalled jumpers and software configurations. The only
field configured set point is duct static pressure. An Operation Manual is shipped with each VAV unit. This manual should
be used if the drive needs to be customized for a particular
application.

Fig. 40B — MotormasterT III Sensor Location
(Sizes 038 and 044)

NOTE: The VFD will always provide the proper phase
sequence to the indoor-fan motor. The indoor-fan motor operates in proper rotation regardless of the phase sequence to
the unit. If, upon start-up, the outdoor fans operate backwards but the indoor fan operates in the correct direction,
reverse any two leads to the main terminal block. All fans
will then operate in the correct direction.
To set the duct static pressure, perform the following steps.
The factory setting is zero. The duct transducer has a range
from 0 to 5 in. wg. The transducer output is 4 to 20 mA,
therefore, 0 to 5 in. wg is proportional to the 4 to 20 mA and
must be expressed to the VFD in terms of percentage of the
frequency range. Refer to Table 7. The set point value is a
percentage of the maximum output frequency. Locate the duct
static pressure closest to that desired and use the corresponding set point value. If necessary, interpolation between duct
static pressures is permissible.

START-UP
Use the following information and Start-Up Checklist
on page CL-1 to check out unit PRIOR to start-up.

Unit Preparation — Check that unit has been installed
in accordance with these installation instructions and applicable codes.

Compressor Mounting — Loosen the compressor holddown bolts until sidewise movement of the washer under
each holddown bolt head can be obtained. Do not loosen
completely as bolts are self-locking and will maintain
adjustment.

Service Valves — Ensure that the suction, discharge,
and liquid line service valves are open. Damage to the compressor could result if they are left closed.
31

the base module closes contacts, activating two exhaust fans.
When the economizer position reaches 75% open, the base
module activates the other two exhaust fans. The fans will
turn off when the economizer closes below the same points.
The economizer position set points that trigger the exhaust
fans can be modified, but only through use of the Service
Tool, Comfort Works, or Building Supervisor software. If
single-stage operation is desired, adjust the economizer set
points to identical values at the desired point to activate all
exhaust fans.
The optional modulating power exhaust (VAV standard,
CV optional) is controlled by a modular electronic sequencer system. This system consists of a model R353 signal input module and 4 model S353 staging modules. The
signal input module receives a 0 to 10 vdc signal from the
building pressure transducer, which is mounted adjacent to
the supply static transducer behind the filter access panel.
The modules are mounted just below the unit control board.
The left module is the R353, and the 4 modules on the right
are S353 modules for stages 1 through 4. On the unit wiring
label, the R353 is designated PESC, and the S353 modules
are designated PES1 through PES4.
The building pressure transducer range is −0.5 to
+ 0.5 in. wg. It is powered by a 0 to 10 vdc signal. A factoryinstalled hose at the ‘‘Lo’’ connection leads to atmosphere,
and a field-supplied hose must be connected to the ‘‘Hi’’ connection and led into the building to a point where building
pressure is to be controlled (positive-pressure building). There
is a plug button in the bulkhead just above the transducers,
for use in leading the hoses into the building via the return
air ductwork.
There are 3 adjustments at the R353 module, all of which
have been factory set. In the center of the circuit board is
a set of 4 pins with a jumper, labeled J2. This determines the
mode of operation. The bottom two pins must be jumpered
for direct operation. Direct operation means that the staging modules are activated in sequence as the input signal
increases.

To set the VFD, the VFD must be powered up; however,
since it is located near the indoor air fan, operation of the
fan is not desirable. To disable the fan, perform the following procedure:
1. Open the indoor fan circuit breaker.
2. Remove the jumper between CC and ST on the terminal
strip of the VFD (see Fig. 41).
3. Close the indoor fan circuit breaker. The VFD now is
powered but the fan will not operate.
4. On the front of the VFD is a keypad and display which
will be used to enter the set point. To access this field,
press the ‘‘PRG’’ key until the display reads ‘‘S.PrG’’
(Speed Group Parameters). Press the arrow key until ‘‘Sr1’’
is displayed. This is the VFD set point listed in Table 7.
5. Press the ‘‘READ/WRITE’’ key. The set point value will
be displayed. Use the up-arrow or down-arrow key to
adjust the set point value to the value desired.
6. Press the ‘‘READ/WRITE’’ key again to enter the new
value.
7. Check the factory default values.
IMPORTANT: The Carrier factory default values
for the VFD may be different than the default values of the manufacturer. Refer to the Carrier literature when checking default values. The following
default values have been changed from the manufacturer settings to more closely match the VFD
operation to a Carrier VAV unit.
SETUP PARAMETERS (Item 6, Point 1, Output Frequency) — The default value should be 20.
JUMP FREQUENCY GROUP (Item 7, PID Set Point
Control Select) — The default value is 1.
JUMP FREQUENCY GROUP (Item 8, Proportional Gain)
— The default value is 100.
JUMP FREQUENCY GROUP (Item 9, Integral Gain)
— The default value is 50.
SPEED GROUP PARAMETERS (Item 2, Multi-Speed
Run Frequency No. 1) — The factory setting is 30.
SPEED GROUP PARAMETERS (Item 2, Fire Speed
Override Frequency) — The factory setting is 60.
8. Open the indoor fan circuit breaker.
9. Replace the jumper between CC and ST on the terminal
strip of the VFD.
10. Close the indoor fan circuit breaker; the VFD now is
powered and the fan will operate.
NOTE: Any field measurement of supply fan amps must be
taken with an RMS meter between the fan circuit breaker
and fan contactor (upstream of VFD).

Table 7 — VFD Supply Air Pressure Set Point
PRESSURE
(in. wg)
0
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.00
3.25
3.50

Power Exhaust — The optional non-modulating power
exhaust (CV only) is a two-stage design where the operation
of the exhaust fans is linked to economizer position. When
the supply fan is running and the economizer is 25% open,

CONTROL
(mA)
4.0
4.8
5.6
6.4
7.2
8.0
8.8
9.6
10.4
11.2
12.0
12.8
13.6
14.4
15.2

VFD
SET POINT
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42

VFD — Variable Frequency Drive

(SS2) (SS3)
FLA

FLB

FLC

P24

RCH LOW

NOTE: Terminal strip is located inside the VFD at the bottom.

JOG

AD2

–

D P D P

Fig. 41 — VFD Factory-Installed Jumpers

SS1

JUMPERS

RST

brated in 1% increments, and is factory set at approximately
3%. It is recommended to leave the set point at 3%, to minimize cycling of the fans.
The offset and differential potentiometers have been factory set for atmospheric pressure. Do not change these
settings until there is some experience with the building. In
most cases the factory settings will be satisfactory. However, if the building pressure is not being maintained as desired, then some minor adjusting on a trial and error basis
can be made.

At the upper right corner of the board is a set of 5 pins and
jumper, which determines the time constant for the control.
The time constant is the delay in response built into the controls. The jumper should be on the middle or bottom two
pins, for the maximum time constant. The delay can be
decreased, if desired, by moving the jumper progressively
upward, always jumpering adjacent pins.
At the lower left corner of the board below the terminal
strip is a resistor marked R27. This must be removed in
order to obtain the 0 to 10 vdc signal output. There will not
be a resistor on a factory-supplied module, but a resistor may
be present on a replacement module and must be removed.
The R353 module has a terminal block with 7 connections available for wiring. The 2 right-hand terminals are for
the 24 vac and common connections. The next 2 terminals
are for the 0 to 10 vdc signal. Consult the wiring label for
wire identification if replacing the module. The 3 left-hand
terminals are not used for this application.
The S353 module has an LED (light-emitting diode), a set
of 4 jumper pins, and 2 potentiometers. The LED will light
whenever the module is activated, providing a visual indication of the number of exhaust fans running. The jumper
pins are arranged in a square format. Two jumpers are used
to determine the mode of operation (direct or reverse). The
2 jumpers must be arranged horizontally for direct action
(factory set).
At the top of the module are two potentiometers. The left
potentiometer adjusts the offset. The right potentiometer
adjusts the differential. The potentiometers are factory set
for a nominal 0 in. wg building pressure.
The offset set point is defined as the point at which a module turns off a fan, and is measured in terms of percent of the
input signal. For control purposes, 0 offset is at an arbitrary
‘‘floor’’ which is established at 10% of the input signal, or
1 vdc. In this example, the first stage will turn off at 30%
(3 vdc), and the offset potentiometer will be set at 20%.
The second stage will turn off at 50% signal (5 vdc), and the
offset potentiometer will be set at 40%. The fourth stage is
at the maximum 75% offset, which equates to 85% signal
or 8.5 vdc. The offset potentiometer is calibrated in 10%
increments.
Table 8 relates building pressure to signal level.

Direct Digital Controls DIP Switch Configuration — The Direct Digital Control (DDC) board must be
configured for each application. The DDC board is configured through the DIP switches located on the board. There
are 8 DIP switches which configure 8 different applications
of the DDC. See Table 10. DIP switch 1 is on the left of the
block. DIP switch 8 is on the right of the block. To open a
DIP switch, push the switch up with suitable tool (smallblade screwdriver). To close a DIP switch, push the switch
down. Factory settings are shown in Table 11.
The DIP switch configurations are as follows:
• DIP switch 1 configures the unit to operate as a VAV or
CV unit
• DIP switch 2 configures the unit to use a space sensor (VAV
units) or a thermostat (CV units)
• DIP switch 3 configures the DDC for use with an electronic expansion board
• DIP switch 4 is used to field test the unit
• DIP switch 5 is used to enable occupied heating (VAV units)
or specify the type of power exhaust (CV units)
• DIP switch 6 configures the Time Guardt override and,
when used with the field test function, sets the minimum
damper position
• DIP switch 7 configures the unit for gas heat or electric
heat
• DIP switch 8 configures the unit for heat pump or air conditioner operation.

Crankcase Heater — Units are equipped with crankcase heaters. Crankcase heaters are energized as long as there
is power supplied to unit. Crankcase heaters deenergize while
compressors are running.

Table 8 — Potentiometer Signal Levels
BUILDING PRESSURE
(in. wg)
−0.50
−0.25
0.00
0.25
0.50

IMPORTANT: To prevent damage to compressors, crankcase heater should be energized 24-hours prior to
start-up.

SIGNAL LEVEL
(vdc)
2
4
6
8
10

Evaporator Fan — Fan belt and fixed pulleys are factoryinstalled. See Tables 12-16 for fan performance and motor
limitations data. Remove tape from fan pulley, and be sure
that fans rotate in the proper direction. See Table 17 for air
quantity limits. Static pressure drop for power exhaust is negligible. To alter fan performance, see Evaporator Fan
Performance Adjustment section on page 46.

If the building pressure is controlled at 0 in. wg, offset of
the first stage should be set at 50%, which equates to 60%
of the input signal, or 6 vdc. The other stages can then be set
as desired between 50% and 75%.
The default offset set points for modulating power exhaust are shown in Table 9.
The differential set point is the difference between the
turn off point and the turn on point for each module. It also
is calibrated in terms of percent of input signal, and has a
range of 1% to 7%. The differential potentiometer is cali-

Condenser Fans and Motors — Condenser fans and
motors are factory set. Refer to Condenser-Fan Adjustment
section on page 47 as required. Be sure that fans rotate in
the proper direction. Fan no. 2 (sizes 024-034) and fans
no. 3 and 4 (sizes 038-048) are cycled on the outdoor-air
temperature.

Table 9 — Power Exhaust Default Set Points
STAGE

OFFSET

DIFFERENTIAL

OFF VOLTAGE

ON VOLTAGE

1
2
3
4

50%
55%
60%
64%

3%
3%
3%
3%

6.0
6.5
7.0
7.4

6.3
6.8
7.3
7.7

OFF STATIC PRESSURE
(in. wg)
0.00
0.06
0.12
0.18

Table 10 — DIP Switch Configuration
SETTING

VAV — Space Sensor
Installed
OPEN

VAV

Expansion
Board

Field Test
ON

Base Control
Board Only

Field Test
OFF

CV — CCN or Sensors
Used

VAV — No Space Sensor
CLOSED

CV
CV — Thermostat

LEGEND
CCN — Carrier Comfort Network
CV
— Constant Volume
VAV — Variable Air Volume

5
VAV —
Occupied
Heat
Enabled
CV —
Modulated
Power
Exhaust
VAV —
Occupied
Heat
Disabled
CV —
Constant
Volume
Power
Exhaust

Gas Heat

Heat Pump
Operation

Electric Heat

Air Conditioner
Operation

Time GuardT Override
ON
IN CONJUNCTION
WITH FIELD TEST
— Set Minimum
Damper Position

Time Guard Override
OFF

NOTES:
1. The OPEN side of the DIP switch is marked ‘‘OPEN.’’ When the
rocker switch is on the ‘‘OPEN’’ side of the switch, the switch is
OPEN.
2. The configuration of DIP switches 2 and 5 are dependent on DIP
switch 1. If DIP switch 1 is set to OPEN (VAV operation), then DIP
switches 2 and 5 will configure VAV functions.
3. When the unit is field-tested (DIP switch 4 to OPEN), the function
of DIP switch 6 changes and it is used to set the minimum damper
position.

Table 11 — DIP Switch Factory Settings
UNIT
48EJ,EW
48EK,EY

1
Closed
Open

2
Closed
Closed

3
Closed
Closed

4
Closed
Closed

5
Closed
Closed

6
Closed
Closed

7
Open
Open

8
Closed
Closed

Table 12 — Fan Performance, 48EJ/EK024-034 — Vertical Discharge Units
(For EW/EY units, reduce net available external static pressure by 0.3 in. wg)
AIRFLOW
(Cfm)
4,000
5,000
6,000
7,000
8,000
8,250
9,000
10,000
11,000
12,000
12,500
13,000
13,750
14,000
15,000

AIRFLOW
(Cfm)
4,000
5,000
6,000
7,000
8,000
8,250
9,000
10,000
11,000
12,000
12,500
13,000
13,750
14,000
15,000

0.2
Rpm
340
384
432
483
536
549
590
645
701
757
786
814
857
871
929

Bhp
0.83
1.25
1.79
2.48
3.33
3.57
4.34
5.54
6.92
8.49
9.36
10.28
11.75
12.27
14.50

0.4
Rpm
416
453
495
540
588
600
637
689
741
795
822
849
890
904
960

1.8
Rpm
759
780
805
834
866
874
901
938
977
1019
1040
1062
1095
1106
1152

Bhp
3.97
4.53
5.23
6.09
7.10
7.38
8.29
9.65
11.19
12.94
13.88
14.88
16.48
17.04
19.41

Bhp
1.17
1.61
2.19
2.91
3.78
4.02
4.82
6.04
7.44
9.04
9.92
10.84
12.34
12.86
15.10

2.0
Rpm
796
816
840
868
899
907
932
968
1006
1047
1067
1089
1121
1132
1177

Bhp
4.42
4.99
5.70
6.57
7.60
7.89
8.80
10.18
11.75
13.51
14.46
15.47
17.08
17.64
20.04

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.6
0.8
1.0
1.2
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
480
1.52
537
1.90
588
2.29
635
2.69
513
1.99
566
2.39
615
2.79
660
3.21
550
2.59
600
3.01
647
3.43
690
3.87
591
3.33
638
3.77
682
4.22
723
4.67
635
4.23
679
4.69
720
5.16
759
5.64
646
4.48
690
4.95
730
5.42
769
5.90
681
5.30
722
5.78
762
6.27
799
6.77
729
6.54
768
7.04
805
7.56
840
8.07
779
7.96
816
8.49
850
9.03
884
9.56
830
9.59
865 10.14
898 10.69
929 11.25
856 10.47
890 11.03
922 11.60
953 12.16
883 11.41
915 11.98
946 12.56
976 13.13
922 12.92
953 13.51
983 14.10 1012 14.69
936 13.45
966 14.05
996 14.64 1025 15.23
990 15.71 1019 16.33 1047 16.94 1074 17.55

Rpm
679
703
730
762
797
806
834
874
916
960
983
1006
1041
1053
1101

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
2.2
2.4
2.6
2.8
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
831
4.87
865
5.34
897
5.81
929
6.30
851
5.45
884
5.93
916
6.41
946
6.90
874
6.18
906
6.67
937
7.16
968
7.66
901
7.07
932
7.56
962
8.07
992
8.58
930
8.11
961
8.62
990
9.14 1019
9.67
938
8.40
968
8.92
998
9.44 1026
9.97
963
9.33
992
9.86 1021 10.39 1049 10.93
997 10.72 1026 11.27 1054 11.82 1081 12.37
1035 12.30 1062 12.87 1089 13.43 1115 14.00
1074 14.08 1100 14.66 1126 15.24 1152 15.83
1094 15.05 1120 15.63 1146 16.22 1171 16.82
1115 16.06 1140 16.66 1166 17.25 1190 17.86
1147 17.68 1172 18.29 1196 18.90
—
—
1157 18.25 1182 18.86
—
—
—
—
1200 20.66
—
—
—
—
—
—

Rpm
959
976
997
1020
1047
1054
1076
1107
1141
1177
1195
—
—
—
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
3.4
3.6
3.8
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
1017
7.79
1045
8.30
1072
8.82
1033
8.42
1061
8.94
1087
9.46
1053
9.21
1080
9.73
1106
10.27
1075
10.16
1102
10.69
1127
11.24
1100
11.28
1126
11.83
1151
12.38
1107
11.59
1133
12.14
1158
12.69
1128
12.58
1153
13.14
1178
13.70
1158
14.06
1183
14.63
—
—
1190
15.74
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

1.4
Bhp
3.11
3.64
4.31
5.14
6.12
6.39
7.27
8.59
10.10
11.81
12.73
13.71
15.28
15.83
18.17

1.6
Rpm
720
742
769
799
832
841
868
906
947
990
1012
1034
1068
1080
1127

3.0
Bhp
6.79
7.40
8.17
9.10
10.20
10.50
11.48
12.93
14.57
16.42
17.41
—
—
—
—

Bhp
3.53
4.08
4.77
5.61
6.61
6.88
7.77
9.12
10.65
12.37
13.31
14.30
15.88
16.43
18.79

3.2
Rpm
988
1005
1025
1048
1074
1081
1102
1133
1166
1201
—
—
—
—
—

Bhp
7.28
7.91
8.69
9.63
10.74
11.04
12.03
13.49
15.15
17.01
—
—
—
—
—

LEGEND
Bhp — Brake Horsepower
NOTES:
1. Fan performance is based on wet coils, economizer, roof curb,
cabinet losses, and clean 2-in. filters.
2. Conversion — Bhp to watts:
Bhp x 746
Watts =
Motor efficiency
3. Variable Air Volume units will operate down to 70 cfm/ton. Performance at 70 cfm/ton is limited to unloaded operation and may
be additionally limited by edb (entering dry bulb) and ewb (entering wet bulb) conditions.

Table 13 — Fan Performance, 48EJ,EK038,044 — Vertical Discharge Units
(For EW/EY units, reduce net available external static pressure by 0.5 in. wg)
AIRFLOW
(Cfm)
7,000
8,000
9,000
10,000
11,000
12,000
13,000
14,000
15,000
16,000
17,000
18,000
19,000
20,000

AIRFLOW
(Cfm)
7,000
8,000
9,000
10,000
11,000
12,000
13,000
14,000
15,000
16,000
17,000
18,000
19,000
20,000

0.2
Rpm
429
475
523
571
620
670
720
771
822
873
924
976
1027
1079

Bhp
1.70
2.36
3.11
4.00
5.04
6.24
7.61
9.15
10.88
12.80
14.91
17.24
19.77
22.53

0.4
Rpm
484
525
567
612
658
705
752
801
850
899
949
999
1050
1100

1.8
Rpm
794
813
835
862
891
924
958
995
1033
1073
1114
1156
—
—

Bhp
5.20
6.06
7.09
8.28
9.64
11.18
12.91
14.83
16.96
19.31
21.88
24.69
—
—

Bhp
2.40
3.09
3.97
5.01
6.22
7.61
9.19
10.97
12.95
15.16
17.59
20.26
23.17
26.33

2.0
Rpm
832
848
869
893
921
952
986
1021
1058
1097
1137
1178
—
—

Bhp
5.62
6.52
7.56
8.77
10.15
11.71
13.45
15.40
17.55
19.92
22.51
25.33
—
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.6
0.8
1.0
1.2
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
536
2.70
584
3.10
630
3.50
674
3.90
571
3.49
616
3.90
658
4.31
699
4.74
610
4.39
651
4.82
690
5.26
728
5.71
651
5.46
689
5.91
725
6.37
761
6.84
694
6.69
729
7.17
763
7.65
796
8.14
738
8.10
771
8.60
803
9.11
834
9.62
784
9.70
814 10.23
844 10.75
874 11.29
830 11.51
859 12.05
887 12.60
915 13.15
877 13.52
904 14.08
931 14.65
957 15.22
925 15.74
951 16.33
976 16.92 1001 17.51
974 18.20
998 18.80 1022 19.41 1045 20.03
1023 20.88 1046 21.51 1068 22.14 1091 22.77
1072 23.82 1094 24.46 1115 25.11 1137 25.76
1122 27.00 1142 27.66 1163 28.33 1183 29.00

Rpm
716
738
765
795
829
865
902
942
983
1025
1069
1113
1158
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
2.2
2.4
2.6
2.8
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
868
6.06
903
6.52
937
6.98
971
7.44
883
6.98
916
7.45
949
7.92
981
8.40
902
8.04
934
8.53
965
9.02
995
9.52
925
9.27
955
9.77
985 10.28 1014 10.79
951 10.67
980 11.19 1008 11.71 1036 12.24
980 12.24 1008 12.78 1035 13.32 1062 13.87
1012 14.01 1039 14.56 1064 15.13 1090 15.69
1046 15.97 1071 16.55 1096 17.13 1120 17.71
1082 18.14 1106 18.73 1130 19.33 1153 19.93
1120 20.52 1143 21.14 1165 21.75 1188 22.37
1159 23.13 1181 23.76
—
—
—
—
1199 25.98
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

Rpm
1003
1012
1025
1043
1064
1088
1115
1144
1176
—
—
—
—
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
3.4
3.6
3.8
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
1066
8.88
1096
9.38
1125
9.88
1072
9.88
1101
10.39
1130
10.90
1083
11.04
1111
11.56
1139
12.08
1098
12.37
1125
12.90
1152
13.44
1117
13.86
1143
14.41
1169
14.96
1139
15.54
1164
16.11
1189
16.68
1164
17.41
1188
17.99
—
—
1191
19.48
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

1.4
Bhp
4.30
5.17
6.16
7.31
8.64
10.13
11.82
13.71
15.80
18.11
20.64
23.41
26.42
—

1.6
Rpm
756
776
801
829
860
894
931
969
1008
1049
1092
1135
1179
—

3.0
Bhp
7.92
8.89
10.02
11.31
12.78
14.42
16.26
18.29
20.54
—
—
—
—
—

Bhp
4.80
5.61
6.62
7.79
9.14
10.65
12.36
14.27
16.38
18.71
21.26
24.05
27.07
—

3.2
Rpm
1035
1042
1054
1071
1090
1114
1140
1168
1199
—
—
—
—
—

Bhp
8.40
9.38
10.53
11.84
13.32
14.98
16.83
18.89
21.14
—
—
—
—
—

Table 14 — Fan Performance, 48EJ,EK048 — Vertical Discharge Units
(For EW/EY units, reduce net available external static pressure by 0.5 in. wg)
AIRFLOW
(Cfm)
9,000
10,000
11,000
12,000
13,000
14,000
15,000
16,000
17,000
18,000
19,000
20,000

AIRFLOW
(Cfm)
9,000
10,000
11,000
12,000
13,000
14,000
15,000
16,000
17,000
18,000
19,000
20,000

0.2
Rpm
528
577
627
677
728
779
830
882
934
986
1038
1091

Bhp
3.20
4.10
5.10
6.30
7.71
9.28
11.03
12.97
15.12
17.47
20.05
22.84

0.4
Rpm
572
617
664
711
760
809
858
908
959
1010
1061
1112

1.8
Rpm
839
866
897
930
965
1002
1041
1082
1124
1166
—
—

Bhp
7.10
8.40
9.70
11.30
13.04
14.99
17.15
19.52
22.14
24.98
—
—

Bhp
4.00
5.10
6.30
7.70
9.31
11.11
13.13
15.36
17.83
20.53
23.49
26.69

2.0
Rpm
873
898
927
958
992
1028
1066
1105
1146
1188
—
—

Bhp
7.62
8.85
10.24
11.82
13.59
15.56
17.74
20.14
22.77
25.63
—
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
0.6
0.8
1.0
1.2
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
615
4.40
656
4.90
695
5.30
733
5.80
657
5.50
694
6.00
731
6.40
766
6.90
700
6.80
735
7.30
769
7.70
802
8.20
745
8.20
778
8.70
809
9.20
841
9.70
791
9.83
822 10.35
851 10.88
881 11.42
838 11.65
867 12.20
895 12.75
923 13.31
886 13.69
913 14.26
939 14.83
966 15.41
934 15.95
960 16.54
985 17.13 1010 17.73
983 18.44 1008 19.05 1031 19.66 1055 20.28
1033 21.16 1056 21.79 1078 22.42 1101 23.06
1083 24.13 1105 24.78 1126 25.44 1147 26.09
1133 27.36 1154 28.03 1174 28.70 1195 29.37

Rpm
769
801
835
871
909
950
991
1034
1078
1123
1169
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
2.2
2.4
2.6
2.8
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
905
8.10
937
8.59
968
9.08
999
9.57
929
9.34
959
9.85
989 10.36 1018 10.87
956 10.76
985 11.28 1013 11.81 1041 12.34
986 12.36 1014 12.90 1041 13.44 1067 13.99
1019 14.15 1045 14.71 1071 15.27 1096 15.84
1054 16.14 1079 16.71 1103 17.30 1127 17.88
1090 18.34 1114 18.93 1138 19.53 1161 20.13
1128 20.75 1151 21.37 1174 21.99 1196 22.61
1168 23.40 1190 24.03
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

Rpm
1028
1047
1068
1093
1121
1151
1184
—
—
—
—
—

1.4
Bhp
6.20
7.40
8.70
10.20
11.95
13.87
15.99
18.33
20.89
23.70
26.75
—

1.6
Rpm
805
834
866
901
938
976
1017
1058
1101
1145
1190
—

3.0
Bhp
10.08
11.39
12.87
14.54
16.41
18.47
20.74
—
—
—
—
—

Bhp
6.70
7.90
9.20
10.80
12.50
14.43
16.57
18.93
21.52
24.34
27.41
—

3.2
Rpm
1057
1075
1095
1119
1146
1175
—
—
—
—
—
—

Bhp
10.58
11.91
13.41
15.10
16.98
19.06
—
—
—
—
—
—

AVAILABLE EXTERNAL STATIC PRESSURE (in. wg)
3.4
3.6
3.8
Rpm
Bhp
Rpm
Bhp
Rpm
Bhp
1086
11.10
1114
11.61
1141
12.14
1102
12.44
1129
12.97
1155
13.51
1122
13.96
1147
14.51
1173
15.06
1144
15.66
1169
16.23
1194
16.80
1170
17.56
1194
18.14
—
—
1198
19.66
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

3. Variable Air Volume units will operate down to 70 cfm/ton. Performance at 70 cfm/ton is limited to unloaded operation and may
be additionally limited by edb and ewb conditions.

Table 15 — Fan Performance — Power Exhaust
48EJ,EK,EW,EY024-048 (20 THRU 45 TONS)
Low Speed
Airflow
208
v
230, 460, 575 v
(Cfm)
ESP Bhp Watts ESP Bhp Watts
6,500 0.32 2.82 3160 0.70 2.98 3340
6,700 0.23 2.87 3220 0.63 3.03 3400
6,900 0.17 2.92 3270 0.59 3.09 3460
7,100 0.13 2.93 3290 0.56 3.11 3490
7,300 0.09 2.97 3330 0.53 3.15 3530
7,500
———0.51 3.19 3580
7,700
———0.48 3.23 3620
7,900
———0.45 3.27 3670
8,100
———0.40 3.33 3730
8,500
——————8,900
——————9,300
——————9,700
——————10,100
——————10,500
——————10,900
——————11,300
——————11,700
——————-

ESP
—
0.60
0.55
0.49
0.43
0.39
0.33
0.27
0.22
0.17
0.00
———————-

208 v
Bhp
—3.01
3.07
3.12
3.18
3.24
3.27
3.32
3.36
3.47
3.58
———————-

Medium Speed
230, 460, 575 v
Watts ESP Bhp Watts
————3380 0.82 3.23 3620
3440 0.78 3.28 3680
3500 0.73 3.34 3740
3560 0.68 3.39 3800
3630 0.64 3.44 3860
3670 0.59 3.48 3900
3720 0.54 3.52 3950
3770 0.49 3.57 4000
3890 0.40 3.67 4120
4010 0.30 3.77 4230
—0.22 3.87 4340
—0.16 3.95 4430
—0.12 4.03 4520
————————————————-

ESP
——————0.60
0.56
0.51
0.41
0.31
0.20
0.11
0.04
————-

208 v
Bhp
——————3.69
3.74
3.78
3.83
3.93
4.07
4.17
4.25
————-

High Speed
230, 460, 575 v
Watts ESP Bhp Watts
————————————————————————4140 0.73 3.98 4460
4190 0.69 4.02 4510
4240 0.65 4.07 4560
4290 0.56 4.12 4620
4410 0.47 4.23 4740
4560 0.37 4.37 4900
4670 0.30 4.47 5010
4770 0.23 4.56 5110
—0.17 4.66 5220
—0.12 4.75 5330
—0.07 4.80 5380
—0.04 4.83 5420

LEGEND
Bhp — Brake Horsepower
ESP — External Static Pressure (in. wg)
Watts — Input Watts to Motor

Table 16 — Motor Limitations
Nominal
Hp
5
7.5
10
15
20
25
30

Nominal
Hp
5
7.5
10
15
20
25
30

Maximum
Bhp
5.9
5.9
8.7
9.5
10.2
11.8
15.3
18.0
22.4
23.4
28.9
29.4
35.6
34.7

STANDARD EFFICIENCY MOTORS
Maximum Amps
230
460
575
14.6
—
—
—
7.9
6.0
22.0
—
—
—
12.0
10.0
28.0
—
—
—
14.6
12.0
43.8
—
—
—
21.9
19.0
62.0
—
—
—
28.7
23.0
72.0
—
—
—
37.4
31.0
95.0
—
—
—
48.0
47.0
HIGH EFFICIENCY MOTORS
Maximum Amps
230
460
15.8
—
—
7.9
22.0
—
—
12.0
28.0
—
—
15.0
43.8
—
—
21.9
58.2
—
—
28.7
73.0
—
—
36.3
82.6
—
—
41.7

Maximum
Watts

Motor
Efficiency

5,030
5,030
7,334
8,008
8,502
9,836
12,543
14,756
18,363
19,183
23,511
23,918
28,742
28,015

87.5
87.5
88.5
88.5
89.5
89.5
91.0
91.0
91.0
91.0
91.7
91.7
92.4
92.4

Maximum
Watts

Motor
Efficiency

4,918
4,918
7,078
7,728
8,298
9,600
12,273
14,439
17,853
18,650
23,034
23,432
28,374
27,656

89.5
89.5
91.7
91.7
91.7
91.7
93.0
93.0
93.6
93.6
93.6
93.6
93.6
93.6

BHP — Brake Horsepower
NOTE: Extensive motor and electrical testing on the Carrier units has ensured that the full horsepower range of the motor can be utilized with
confidence. Using your fan motors up to the horsepower ratings shown on the Motor Limitations table will not result in nuisance tripping or premature
motor failure. Unit warranty will not be affected.

Table 17 — Air Quantity Limits
UNIT
48EJ,EK,EW,EY

MINIMUM HEATING
AIRFLOW
(Low Heat)

MINIMUM HEATING
AIRFLOW
(High Heat)

024
028
030
034
038
044
048

5730
5730
5730
5730
7360
7360
7360

5950
5950
5950
5950
9820
9820
9820

MINIMUM COOLING
AIRFLOW (VAV)
AT FULL LOAD
OPERATION
2000
2500
2750
3000
3500
4000
4500

MINIMUM COOLING
AIRFLOW (CV)

MAXIMUM
AIRFLOW

6,000
7,500
8,250
9,000
10,500
12,000
13,500

10,000
12,500
13,750
15,000
17,500
20,000
22,500

LEGEND
CV — Constant Volume
VAV — Variable Air Volume

open,then sensors are employed. If switch no. 2 is closed,
thermostat is employed. Initialization clears all alarms and
alerts, remaps the input/output database for CV operation,
sets maximum heat stages to 2, and sets maximum cool stages
to 3. The control reads DIP switch no. 3 and if open, then it
sets the internal flag for expansion mode operation.
The first time power is sent to the control board after a
power outage, power up takes 5 minutes plus a random 1 to
63 seconds.
The TSTAT function performs a thermostat based control
by monitoring Y1, Y2, W1, W2, and G inputs. These functions control stages cool1, cool2, heat1, heat2, and indoor
fan, respectively. If TSTAT function is NOT selected, the
control determines the occupancy state on the Time Schedules or with remote occupied/unoccupied input. If temperature compensated start is active, the unit will be controlled
as in the Occupied mode. User-defined set points are shown
in Table 18.
The occupied or unoccupied comfort set points must be
selected and the space temperature offset input will be used,
if present. The Occupied Heat set point default value is
68 F. The Occupied Cool set point default value is 78 F. The
Unoccupied Heat set point default value is 55 F. The Unoccupied Cool set point value is 90 F. The control board will
set appropriate operating mode and fan control. The control
board will turn on indoor fan, if in Occupied mode, or determine if unit is in Unoccupied mode and the space temperature is outside of the unoccupied comfort set points,
(Unoccupied Heat or Unoccupied Cool).
The control board will then monitor space temperature against
comfort set points and control heating or cooling stages as
required. If system is in the Occupied mode, the economizer
will operate as required. If the system is in Unoccupied
mode, the system will perform nighttime free cool and IAQ
(indoor air quality) pre-occupancy purge as required (when
functions are enabled via software). Whenever the DX
(di-rect expansion) cooling is requested, the outdoor fan will
operate.
The control board will operate economizer, run diagnostics to monitor alarms/alerts at all times, and respond to CCN
communications to perform any configured network POC
(product outboard control) functions such as time and outdoorair temperature broadcast and Global occupancy broadcast.
When the optional expansion I/O board is employed, it will:
perform periodic scan and maintain database of expanded
I/O points, perform Fire/Smoke control (power exhaust required); and if in Occupied mode perform IAQ control and
monitor fan, filter, demand limit, and field-applied status (with
accessories).
If thermostats are used to energize the G input, the control
will turn on indoor fan without delay and open economizer
dampers to minimum position.

Return-Air Filters — Check that correct filters are installed in filter tracks (see Table 1). Do not operate unit without return-air filters.

Filter Replacement — To replace filters, open filter access door (marked with label). Remove inner access panel.
Remove plastic filter retainer in between filter tracks by sliding and pulling outward. Remove first filter by sliding it out
of the opening in filter track. Locate filter removal tool, which
is shipped next to the return air dampers. Use the filter removal tool to remove the rest of the filters.
Outdoor-Air Inlet Screens — Outdoor-air inlet screens
must be in place before operating unit.

Economizer Adjustment — Remove filter access panel.
Check that outdoor-air damper is closed and return-air damper
is open.
Economizer operation and adjustment are described in
Sequence of Operation section on this page; and Minimum
Damper Position Setting section on page 24.

Gas Heat — Verify gas pressures before turning on heat
as follows:
1. Turn off field-supplied manual gas stop, located external
to unit.
2. Connect pressure gage to supply gas tap, located on fieldsupplied manual shutoff valve (see Fig. 13 on page 13).
3. Connect pressure gage to manifold pressure tap on unit
gas valve.
4. Supply gas pressure must not exceed 13.5 in. wg. Check
pressure at field-supplied shut-off valve.
5. Turn on manual gas stop and initiate a heating demand.
Jumper R to W1 in the control box to initiate heat. On
VAV units, the RAT (Return-Air Temperature) must be
less than or equal to 68 F for heating to be energized. Use
the field test procedure to verify heat operation. After the
unit has run for several minutes, verify that incoming pressure is 5.0 in. wg or greater, and that the manifold pressure is 3.5 in. wg. If manifold pressure must be adjusted,
refer to Gas Valve Adjustment section on page 47.
Sequence of Operation
NOTE: Unit is shipped with default values that can be changed
through Service Tool, Building Supervisor, or ComfortWorks™ software. See Table 18 for default values.
COOLING, CONSTANT VOLUME (CV) UNITS — On
power up, the control module will activate the initialization
software of the control board. The initialization software thenreads DIP switch no. 1 position to determine CV or VAV
operation. Next, DIP switch no. 2 is read to determine if the
control is thermostat or sensor type operation. If switch 2 is
39

Table 18 — User Defined Set Points
SET POINT
NAME
OHSP
OCSP
UHSP
UCSP
SASP
OATL
NTLO
RTIO
LIMT
MDP

FORMAT

LOWMDP

xxx%

IAQS
UHDB
UCDB
LTMP
HTMP
PES1
PES2

xxxx
xx.xF
xx.xF
xxx%
xxx%
xxx%
xxx%

xx.xF
xx.xF
xx.xF
xx.xF
xx.xF
xx.xF
xx.xF
xx.x
xx.xF
xxx%

DESCRIPTION

LIMITS

Occupied Heat Set Point
Occupied Cool Set Point
Unoccupied Heat Set Point
Unoccupied Cool Set Point
Supply Air Set Point
Hi OAT Lockout Temperature
Unoccupied OAT Lockout Temperature
Reset Ratio
Reset Limit
Minimum Damper Position
Low Temperature Minimum
Damper Position Override
IAQ Set Point
Unoccupied Heating Deadband
Unoccupied Cooling Deadband
Low Temp. Min. Position
High Temp. Min. Position
CV Power Exhaust Stage 1 Point
CV Power Exhaust Stage 2 Point

55
55
40
75
45
55
40
0
0
0

to
to
to
to
to
to
to
to
to
to

80 F
80 F
80 F
95 F
70 F
75 F
70 F
10
20° F
100%

0 to 100%
1
0
0
0
0
0
0

to
to
to
to
to
to
to

5000 PPM
10° F
10° F
100%
100%
100%
100%

DEFAULT
68 F
78 F
55 F
90 F
55 F
65 F
50 F
3
10%
20%
100%
650 PPM
1° F
1° F
10%
35%
25%
75%

LEGEND
CV — Constant Volume
IAQ — Indoor Air Quality
OAT — Outdoor-Air Temperature

of the control board. The initialization software then reads
DIP switch no. 1 position to determine CV or VAV operation. Initialization clears all alarms and alerts, re-maps the
input/output database for VAV operation, sets maximum heat
stages to 1 and sets maximum cool stages to 6. The control
reads DIP switch no. 3 and if open, then it sets the internal
flag for expansion mode operation.
The control board will determine if an interface (linkage)
is active and if the unit will operate in a Digital Air Volume
(DAV) mode. In a DAV system, the room terminals are equipped
with microprocessor controls that give commands to the base
unit module. If an interface is active, the control will replace
local comfort set points, space and return air temperatures
and occupancy status with the linkage data supplied.
The control board will determine occupancy status from
Time Schedules (if programmed), Remote Occupied/
Unoccupied input, global occupancy, or DAV. If temperature compensated start is active, the unit will be controlled
as in the Occupied mode.
NOTE: The temperature compensated start is a period of time
calculated to bring the unit on while unoccupied to reach the
occupied set point when occupancy occurs.
The control board will set the appropriate operating mode
and fan control. The control board will turn VFD on if Occupied mode is evident.
For units equipped with a start/stop switch only (no space
temperature sensor), if unoccupied and valid return-air temperature reading is available (either from a sensor or DAV),
the control will monitor return-air temperature against Unoccupied Heat and Cool set points.
For units with a start-stop switch and a space temperature
sensor, the control board will start the VFD whenever SPT
is outside of the set points (Unoccupied Heat or Unoccupied
Cool). The VFD may also be started by nighttime thermostat
via remote Occupied/Unoccupied input or by a temperature
compensated start algorithm. When VFD is running in a normal mode, the control will start heating or cooling as required to maintain supply-air temperature at the supply air
set point plus the reset (when enabled). The reset value is
determined by SAT (supply-air temperature) reset and/or space
temperature reset algorithms. The space temperature reset is
only available when enabled through software.

If thermostats are used to deenergize the G input, the control board will turn off indoor fan without any delay and close
economizer dampers.
When cooling, G must be energized before cooling can
operate. The control board determines if outdoor conditions
are suitable for economizer cooling using the standard outdoor air thermistor. For economizer to function for free cooling, the enthalpy must be low, the outdoor air must equal to
or less than the High Outdoor Air Temperature Lockout (default is 65 F), the SAT (supply-air temperature) thermistor is
NOT in alarm, and outdoor air reading is available. When
these conditions are satisfied, the control board will use economizer as the first stage of cooling.
When Y1 input is energized, the economizer will be modulated to maintain SAT at the defined set point. The default is
55 F. When SAT is above the set point, the economizer will
be 100% open. When SAT is below the set point, the economizer will modulate between minimum and 100% open position. When Y2 is energized, the control will turn on compressor no. 1 and continue to modulate economizer as described
above. If the Y2 remains energized and the SAT reading remains above the set point for 15 minutes, compressor no. 2
will turn on. If Y2 is deenergized at any time, only the last
stage of compression that was energized will be turned off.
If outdoor conditions are not suitable for economizer cooling, the economizer will go to minimum position and cycle
compressor no. 1 and 2 based on demand from Y1 and Y2
respectively. The compressors will be locked out when the
SAT temperature is too low (less than 40 F for compressor
no. 1 and less than 45 F for compressor no. 2.) After a compressor is locked out, it can restart after normal time guard
period.
The Time Guardt function maintains a minimum off time
of 5 minutes, a minimum ON time of 10 seconds, and a
minimum delay before starting the second compressor of
10 seconds.
When heating, the heat stages respond to the demand from
W1 and W2 of the thermostat input. Heating and cooling
will be mutually locked out on demand on a first call basis.
The heating and the cooling functions cannot be operating
simultaneously.
COOLING, VARIABLE VOLUME UNITS — On power up,
the control module will activate the initialization software
40

When cooling, the control will energize the power exhaust enable output to the external power exhaust controller,
when power exhaust is used.
If occupied, the control will perform economizer control
(economizer control same as described above for CV units).
If unoccupied, the control will perform nighttime free cool
and IAQ pre-occupancy purge as required (when enabled
through software). When DX (direct expansion) cooling is
called, the outdoor fans will always operate.
The control will run continuous diagnostics for alarms/
alerts; respond to CCN communications and perform any configured network POC (product outboard controls) functions
such as time and outdoor-air temperature broadcast and global broadcast; and perform Fire/Smoke control if equipped
with power exhaust.
GAS HEATING, CONSTANT VOLUME (CV) UNITS —
The gas heat units incorporate 2 separate systems to provide
gas heat. Each system incorporates its own induced-draft motor, Integrated Gas Control (IGC) board, 2 stage gas valve,
manifold, etc. The systems are operated in parallel; for example, when there is a call for first stage heat, both induceddraft motors operate, both gas valves are energized, and both
IGC boards initiate spark.
All of the gas heating control is performed through the
IGC boards (located in the heating section). The base module board serves only to initiate and terminate heating
operation.
The base module board is powered by 24 vac. When the
thermostat or room sensor calls for heating, power is sent
from the base module board to W on each of the IGC boards.
An LED on the IGC board will be on during normal operation. A check is made to ensure that the rollout switches and
limit switches are closed and the induced-draft motors are
not running. The induced-draft motors are then energized,
and when speed is proven with the hall effect sensor on the
motor, the ignition activation period begins. The burners will
ignite within 5 seconds.
When ignition occurs the IGC board will continue to monitor the condition of the rollout and limit switches, the hall
effect sensor, as well as the flame sensor. If the unit is controlled through a room thermostat set for fan auto., 45 seconds after ignition occurs, the indoor-fan motor will be
energized and the outdoor-air dampers will open to their minimum position. If for some reason the overtemperature limit
opens prior to the start of the indoor fan blower, on the next
attempt, the 45-second delay will be shortened to 5 seconds
less than the time from initiation of heat to when the limit
tripped. Gas will not be interrupted to the burners and heating will continue. Once modified, the fan on delay will not
change back to 45 seconds unless power is reset to the control. If the unit is controlled through a room sensor, the indoor fan will be operating in the Occupied mode and the
outdoor-air dampers will be in the minimum position.
If the unit is controlled with a room sensor in the Unoccupied mode, the indoor fan will be energized through the
IGC board with a 45-second delay and the outside-air dampers will move to the IAQ position (generally closed in the
Unoccupied mode). If IAQ is not enabled, dampers will move
to the minimum position.
When additional heat is required, W2 closes and initiates
power to the second stage of the main gas valves. When the
thermostat is satisfied, W1 and W2 open and the gas valves
close interrupting the flow of gas to the main burners. If the
call for W1 lasted less than 1 minute, the heating cycle will
not terminate until 1 minute after W1 became active. If the
unit is controlled through a room thermostat set for fan auto.,
the indoor-fan motor will continue to operate for an additional 45 seconds then stop and the outdoor-air dampers will

close. If the overtemperature limit opens after the indoor
motor is stopped within 10 minutes of W1 becoming inactive, on the next cycle the time will be extended by 15 seconds. The maximum delay is 3 minutes. Once modified, the
fan off delay will not change back to 45 seconds unless power
is reset to the control. If the unit is controlled through a room
sensor, the indoor fan will be operating in the Occupied mode
and turned off after 45 seconds in the Unoccupied mode.
GAS HEATING, VARIABLE AIR VOLUME (VAV) UNITS
— All of the gas heating control is performed through the
integrated gas control (IGC) board. The base module board
serves only to initiate and terminate heating operation.
NOTE: The unit is factory-configured for disabled occupied
heating. DIP switch 5 is used to enable occupied heating (DIP
switch 5 set to OPEN).
The base module board is powered by 24 vac. When there
is a call for heating (either Morning Warm-Up, Unoccupied,
or Occupied modes), power is sent from the base module
board to W on each of the IGC boards and W2 of the main
gas valve. When heating, the control board will energize a
field-supplied heat interlock relay output to drive the VAV
terminal boxes wide open. The HIR is not required on a DAV
system. See Fig. 42. In the Occupied mode the indoor-fan
motor will be operating and the outdoor-air dampers will be
in the minimum position. In the Unoccupied mode the indoorfan motor will be off, but will energize 45 seconds after the
call for heat and the outdoor-air dampers will move to the
IAQ Unoccupied position (generally set to closed in the Unoccupied mode). The duct pressure sensor will signal to the
variable frequency drive to operate at full speed since all
terminals have been driven open. An LED on the IGC board
will be on during normal operation. A check is made to ensure that the rollout switches and limit switches are closed
and the induced-draft motors are not running. The induceddraft motors are then energized and when speed is proven
with the hall effect sensor on the motor, the ignition activation period begins. The burners will ignite within 5 seconds.
When ignition occurs the IGC board will continue to monitor the condition of the rollout and limit switches, the hall
effect sensor, and the flame sensor.
If the call for heat lasted less than 1 minute, the heating
cycle will not terminate until 1 minute after heat became active. When heating is satisfied, the power will be interrupted
to the IGC board and W1 and W2 of the main gas valve. If
the unit is controlled through a room sensor, the indoor fan
will be operating in the Occupied mode and turned off after
45 seconds in the Unoccupied mode.
MORNING WARM-UP (VAV only) (PC Accessed/CCN
Operation) — Morning warm-up occurs when the control
has been programmed to turn on heat prior to the Occupied
mode to be ready for occupancy mode. Morning warm-up is
a condition in VAV systems that occurs when the Temperature Compensated Start algorithm calculates a biased occupied start time and the unit has a demand for heating. The
warm-up will continue into the occupied period as long as
there is a need for heat. During warm-up, the unit can continue heating into the occupied period, even if occupied heating is disabled. When the heating demand is satisfied, the
warm-up condition will terminate. To increase or decrease
the heating demand, use Service Tool software to change the
Occupied Heating set point.
NOTE: To utilize Morning Warm-Up mode, the unit occupancy schedule must be accessed via Service Tool, Building
Supervisor, or ComfortWorks™ software or accessory LID2B. The PC can access the base control board via the 3-wire
communication bus or via an RJ-11 connection to the CCN
terminal on the base control board. See Fig. 16.

MORNING WARM-UP (VAV Only) (Stand-Alone Operation) — When the unit operates in stand-alone mode, morning warm-up occurs when the unit is energized in Occupied
mode and return-air temperature (RAT) is below 68 F. Warm-up
will not terminate until the RAT reaches 68 F. The heat interlock relay output is energized during morning warm-up.
(A field-installed 24-vdc heat interlock relay is required.) The
output will be energized until the morning warm-up cycle is
complete. Refer to Fig. 42 for heat interlock relay wiring.

in supply-air temperature per degree of space temperature
change. A reset limit will exist which will limit the maximum number of degrees the supply-air temperature may be
raised. (Default is 10 F.) Both the reset ratio and the reset
limit are user definable. The sequence of operation is as
follows:
1. The on/off status of the unit supply fan is determined.
2. If the fan is ‘‘on,’’ the sequence will check if the system
is occupied.
3. If the system is occupied, the sequence will determine if
the reset option is enabled.
4. If the reset option is enabled, the sequence will read the
space temperature and compare it to the Occupied Cool
set point. If the temperature is below the Occupied Cool
set point, the algorithm will compute the reset value and
compare this value against the reset limit. If it is greater
than the reset limit, the sequence will use the reset limit
as the reset value.

SPACE TEMPERATURE RESET SENSOR (VAV Only) —
An accessory space temperature sensor wired to terminals
T1 and T2 on the control module is required. Space temperature reset is used to reset the supply-air temperature set
point of a VAV system higher, as the space temperature falls
below the Occupied Cool set point. As the space temperature falls below the Occupied Cool set point, the supply-air
temperature will be reset upward as a function of the reset
ratio. (Default is 3.) Reset ratio is expressed in degrees change
TRAN2
B
CB4
3.2 AMPS

COM
SECONDARY
24 VOLT

CB
COM
HIR
T
TRAN

BASE MODULE
CONTROL BOARD
INDOOR FAN RELAY

LEGEND
— Circuit Breaker
— Common
— Heat Interlock Relay
— Terminal
— Transformer

COM

T
30

HIR

T29

FIELD
INSTALLED
(HN61KK040)
(24V, 9.5VA)

T
28

Fig. 42 — Heat Interlock Relay Wiring

mA INPUT
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

BASE MODULE
CONTROL BOARD
(+) T11

4-20 mA
INPUT

(–) T12

FIELD
SUPPLIED
INPUT DEVICE

LEGEND
T — Terminal
NOTE: The 4 to 20 mA input is a field-supplied nonCarrier EMS (Energy Management System) device.

Fig. 43 — Space Temperature Reset Wiring
42

DEG. F RESET
0.00
1.25
2.50
3.75
5.00
6.25
7.50
8.75
10.00
11.25
12.50
13.75
15.00
16.25
17.50
18.75
20.00

Space Temperature Reset Example — The occupied cooling
set point is set to 73 F. The Reset Ratio is set to 5. The Reset
Limit is set to 20° F. The Reset Ratio determines how many
degrees F the temperature is reset. At 72 F, the supply temperature will be reset 5 degrees higher. At 71 F, the supply
temperature will be reset 10 degrees higher. At 70 F, the supply temperature will be reset 15 degrees higher. At 69 F, the
supply temperature will be reset 20 degrees higher and the
Reset Limit will have been reached.
SUPPLY AIR TEMPERATURE RESET — Supply air temperature reset is used to reset the supply air temperature utility. A 4 to 20 mA signal (field-supplied) is required. The reset option does not require enabling.
POWER EXHAUST OPERATION — The optional power
exhaust packages are factory- or field-installed with vertical
units and optionally installed in the return air ductwork for
horizontal applications. The standard (offered with constant
volume or variable air volume units) and the modulating power
exhaust (offered on VAV units) are the two packages offered.
The modulating power exhaust package is equipped with a
field-adjustable static pressure controller to stage up to 4 power
exhaust stages which will maintain a building static pressure. The blue controller located in the control box below
the control board can be adjusted, by removing the covers
and adjusting the set point dial to the desired building pressure. The blue controller monitors the 4 individual sequencers which activate the 4 individual power exhaust motors.
The standard power exhaust package controls up to 2 stages
of power exhaust to maintain building pressure. The power
exhaust package can be configured to deliver positive or negative building pressure. These power exhaust stages are staged
according to a percentage of the economizer dampers
position. Default values are 25% for Stage 1 and 75% for
Stage 2. This package has set points that are adjustable
through software (Service Tool, Building Supervisor, or
ComfortWorks™).

Fig. 44 — Field-Supplied Smoke Detector Wiring

as to specific smoke detector location due to liability
considerations.
INDOOR AIR QUALITY CONTROL — The accessory expansion board and accessory IAQ sensor are required for IAQ
control. The Carrier sensors operate with a 4 to 20 mA signal. The 4 to 20 mA signal is connected to T11 (+) and T12
(−) on the expansion board for the IAQ sensor, and T13 (+)
and T14 (−) on the expansion board for the OAQ (Outdoor
Air Quality) sensor. The sensor is field-mounted and wired
to the expansion board installed in the unit main control box.
The IAQ sensor must be powered by a field-supplied 24-v
power supply (ungrounded). Do not use the unit 24-v power
supply to power the sensor.
Once installed, the sensor must be enabled. The sensor is
configured with default values which may be changed through
network access software. To work properly, the IAQ sensor
high and low reference points for the sensor that is used must
match the configured values. The expansion board reacts to
a 4 to 20 mA signal from the IAQ sensor. The low reference
(4 mA output) must be configured to the minimum IAQ sensor reading. The high reference (20 mA output) must be configured to the maximum IAQ sensor reading.
The IAQ sensor can be configured to either low or high
priority. The priority value can be changed by the user. The
default is low.
Low priority — When the priority is set to low, the initial
control is to the IAQ set point, but the outside air damper
position will change to its minimum position when the following conditions occur:
• CV units with sensor — when the space temperature is
greater than the occupied cooling set point plus 2° F or
when the space temperature is less than the occupied
heating set point minus 2° F.
• VAV units and CV units with thermostat — when the
supply-air temperature is less than the supply-air temperature set point minus 8° F or when the supply-air
temperature is greater than the supply air temperature
set point plus 5° F for 4 minutes.

SMOKE CONTROL MODES — The 48EJ,EK,EW,EY units
with an optional expansion board perform fire and smoke
control modes. The expansion board provides 4 modes which
can be used to control smoke within the conditioned area.
The modes of operation are fire shutdown, pressurization,
evacuation, and smoke purge. See Table 19.
SMOKE DETECTOR — A smoke detector can be used to
initiate fire shutdown. This can be accomplished by a set of
normally closed pilot relay contacts which will interrupt power
from the 24-v transformer, secondary ‘‘B’’ terminal to the
control circuit breaker (CB4). See Fig. 44. The wire that connects these two points is white and labeled ‘‘W78.’’
NOTE: On standard gas models, the indoor fan will continue to run 45 seconds after the call for heat has been terminated. If fire shutdown is initiated the fan will stop immediately. No 45-second delay will occur.
The smoke detector may be mounted in the return air duct
or the supply duct. Carrier does not make recommendations

Table 19 — Smoke Control Modes
DEVICE
Economizer
Indoor Fan/VFD
Power Exhaust (all outputs)
Heat Stages
HIR

PRESSURIZATION
100%
ON
OFF
OFF
ON

SMOKE PURGE
100%
ON
ON
OFF
ON

LEGEND
HIR — Heat Interlock Relay
VFD — Variable Frequency Drive

EVACUATION
100%
OFF
ON
OFF
OFF

FIRE SHUTDOWN
0%
OFF
OFF
OFF
OFF

• When the outdoor air quality is greater than the outdoor
air quality set point (ppm)
High priority — When the priority is set to high, the IAQ
set point controls the outside air damper exclusively, with
no regard to comfort conditioning.
TIME GUARDt CIRCUIT — The Time Guard function (built
into the rooftop control board) maintains a minimum off time
of 5 minutes, a minimum on time of 10 seconds, and a
10-second delay between compressor starts.

FIELD TEST — The field test program is initiated by moving up DIP switch no. 4 to the OPEN position. The outdoorair damper will close. The control allows 90 seconds for the
damper to close in case it was in the full open position. Next,
the indoor-fan contactor will be energized, and the outsideair damper will begin to open to its default value of 20% and
stay at that position for a short period of time. The outdoorair damper will then open to its full open position and stay
at that position for a short period of time. The outdoor-air
damper will then close.
If the unit is equipped with power exhaust, stage 1 will be
energized for 5 seconds. If the unit is configured for stage 2
of power exhaust, stage 2 will be energized for 5 seconds
after the first stage is deenergized.
The first stage of heat will be energized for 30 seconds,
after which the second stage heat will be energized for an
additional 30 seconds. Heat is then deenergized.
The last step is the Cooling mode. Outdoor-fan contactor
no. 1 is energized. This is followed by each stage of cooling
energized with a 10-second delay between stages. After this
is complete, outdoor-fan contactor no. 2 is energized for
10 seconds.
The compressors will now deenergize, followed by the
outdoor-fan contactors and indoor-fan contactors. If the unit
is equipped with the Integrated Gas Control (IGC) board,
the indoor fan will continue to operate for an additional
30 seconds after deenergizing the circuit.
The field test is then complete.

CRANKCASE HEATER — Unit main power supply must
remain on to provide crankcase heater operation. The crankcase heater in each compressor keeps oil free of refrigerant
while compressor is off.
HEAD PRESSURE CONTROL — Each unit has a fan cycling, outdoor thermostat to shut off the outdoor-fan motor(s) at 55 F (one outdoor-fan motor on 024-034 units and
two outdoor fan motors on 038-048 units). The head pressure control permits unit to operate with correct condensing
temperatures down to 35 F outdoor-air temperature.
MOTORMASTERt III CONTROL — The Motormaster
III Solid-State Head Pressure Control is a field-installed accessory fan speed control device actuated by a temperature
sensor. It is specifically designed for use on Carrier equipment and controls the condenser-fan motor speed in response to the saturated condensing temperature. For outdoor
temperatures down to −20 F, it maintains condensing temperature at 100 F. Refer to the accessory Motormaster installation instructions for more information.

SERVICE

CAPACITY CONTROL, COOLING — The cooling capacity staging tables are shown in Tables 20 and 21.

Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.

Table 20 — Cooling Capacity Staging Table, CV Units
with 2 Compressors

Service Access — All unit components can be reached

Stages
1
Economizer
off
off

0
Compressor 1
Compressor 2

off
off

on
off

on
on

through clearly labelled hinged access doors. These doors
are not equipped with tiebacks, so if heavy duty servicing is
needed, either remove them or prop them open to prevent
accidental closure.
Each door is held closed with 3 latches. The latches are
secured to the unit with a single 1⁄4-in. - 20 x 1⁄2-in. long bolt.
See Fig. 45.

NOTE: On CV units that require additional unloading, add suction pressure unloaders to Compressor 1 only.

Table 21 — Cooling Capacity Staging Table VAV Units
with 2 Compressors and 2 Unloaders*

Compressor 1
Unloader 1
Unloader 2
Compressor 2

0
off
off
off
off

1
on
on
on
off

2
on
on
off
off

Stages
3
on
off
off
off

4
on
on
on
on

5
on
on
off
on

6
on
off
off
on

*40 ton units have only one unloader.

Fig. 45 — Door Latch

EVAPORATOR COIL — Remove access panels and clean
as required with commercial coil cleaner.

To open, loosen the latch bolt using a 7⁄16-in. wrench. Pivot
the latch so it is not in contact with the door. Open the door.
To shut, reverse the above procedure.
NOTE: Disassembly of the top cover may be required under
special service circumstances. It is very important that the
orientation and position of the top cover be marked on the
unit prior to disassembly. This will allow proper replacement of the top cover onto the unit and prevent rainwater
from leaking into the unit.

CONDENSER COIL — Clean condenser coil annually and
as required by location and outdoor-air conditions. Inspect
coil monthly; clean as required.
CONDENSATE DRAIN — Check and clean each year at
start of cooling season. In winter, keep drains and traps dry.
FILTERS — Clean or replace at start of each heating and
cooling season, or more often if operating conditions require. Refer to Table 1 for type and size.

IMPORTANT: After servicing is completed, make sure
door is closed and relatched properly, and that the latches
are tight. Failure to do so can result in water leakage
into the evaporator section of the unit.

NOTE: The unit requires industrial grade throwaway filters
capable of withstanding face velocities up to 625 fpm.
OUTDOOR-AIR INLET SCREENS — Clean screens with
steam or hot water and a mild detergent. Do not use disposable filters in place of screens. See Fig. 24 for location of
screens (filter track assembly).

Cleaning — Inspect unit interior at beginning of each heating and cooling season and as operating conditions require.
Remove unit side panels and/or open doors for access to unit
interior.
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. Check spark gap. See Fig. 46. Refer to Main Burners section on page 48.

Lubrication
COMPRESSORS — Each compressor is charged with the
correct amount of oil at the factory. The correct oil charge is
shown in Table 1. If oil is visible in the compressor sight
glass, check unit for operating readiness as described in Start-Up
section, then start the unit. Observe oil level and add oil, if
required, to bring oil level in compressor crankcase up to
between 1⁄4 and 1⁄3 of sight glass during steady operation.
If oil charge is above 1⁄3 sight glass, do not remove any oil
until the compressor crankcase heater has been energized for
at least 24 hours with compressor off.
When additional oil or a complete charge is required, use
only Carrier-approved compressor oil:
Petroleum Specialties, Inc. . . . . . . . . . . . . . . . . . Cryol 150
Texaco, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . Capella WF-32
Witco Chemical Corp. . . . . . . . . . . . . . . . . . . . Suniso 3GS

FLUE GAS PASSAGEWAYS — The flue collector box and
heat exchanger cells may be inspected by removing gas section access panel (Fig. 3-6), flue box cover, collector box,
and main burner assembly (Fig. 47 and 48). Refer to Main
Burners section on page 48 for burner removal sequence. If
cleaning is required, clean all parts with a wire brush. Reassemble using new cerafelt high-temperature insulation for
sealing.
COMBUSTION-AIR BLOWER — Clean periodically to assure proper airflow and heating efficiency. Inspect blower
wheel every fall and periodically during heating season. For
the first heating season, inspect blower wheel bi-monthly to
determine proper cleaning frequency.
To inspect blower wheel, remove heat exchanger access
panel. Shine a flashlight into opening to inspect wheel. If
cleaning is required, remove motor and wheel assembly by
removing screws holding motor mounting plate to top of combustion fan housing (Fig. 47 and 48). The motor, scroll, and
wheel assembly can be removed from the unit. Remove scroll
from plate. Remove the blower wheel from the motor shaft
and clean with a detergent or solvent. Replace motor and
wheel assembly.

IMPORTANT: Do not use reclaimed oil or oil that has
been exposed to the atmosphere. Refer to Carrier Standard Service Techniques Manual, Chapter 1, Refrigerants section, for procedures to add or remove oil.
FAN SHAFT BEARINGS — Lubricate bearings at least every 6 months with suitable bearing grease. Do not over grease.
Typical lubricants are given below:
MANUFACTURER
Texaco
Mobil
Sunoco
Texaco

LUBRICANT
Regal AFB-2*
Mobilplex EP No. 1
Prestige 42
Multifak 2

*Preferred lubricant because it contains rust and oxidation inhibitors.

CONDENSER- AND EVAPORATOR-FAN MOTOR BEARINGS — The condenser- and evaporator-fan motors have
permanently-sealed bearings, so no field lubrication is
necessary.
Fig. 46 — Spark Gap Adjustment

NOTES:
1. Torque set screws on blower wheel to 70 in. lbs ± 2 in. lbs.
2. Torque set screw on propeller fan to 15 in. lbs ± 2 in. lbs.
3. Dimensions are in inches.

Fig. 47 — Typical Gas Heating Section
3. Slide fan pulley along fan shaft.
4. Make angular alignment by loosening motor from mounting plate.
5. Retighten pulley.

Evaporator Fan Service and Replacement
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.

Fig. 48 — Gas Heat Section Details

Shut off unit power supply.
Remove supply-air section panels.
Remove belt and blower pulley.
Loosen setscrews in blower wheels.
Remove locking collars from bearings.
Remove shaft.
Remove venturi on opposite side of bearing.
Lift out wheel.
Reverse above procedure to reinstall fan.
Check and adjust belt tension as necessary.

Belt Tension Adjustment — To adjust belt tension:
Evaporator Fan Performance Adjustment
(Fig. 49) — Fan motor pulleys are designed for speed shown

1.
2.
3.
4.

Shut off unit power supply.
Loosen motor mounting nuts and bolts. See Fig. 50.
Loosen fan motor nuts.
Turn motor jacking bolts to move motor mounting plate
left or right for proper belt tension. A slight bow should
be present in the belt on the slack side of the drive while
running under full load.
5. Tighten nuts.
6. Adjust bolts and nut on mounting plate to secure motor
in fixed position. Recheck belt tension after 24 hours of
operation. Adjust as necessary.

in Table 1 (factory speed setting).
IMPORTANT: Check to ensure that the unit drive
matches the duct static pressure using Tables 12-14.
To change fan speeds, change pulleys.
To align fan and motor pulleys:
1. Shut off unit power supply.
2. Loosen fan shaft pulley bushing.

Evaporator-Fan Motor Replacement
1. Shut off unit power supply.
2. Remove upper outside panel and open hinged door to
gain access to motor.
3. Fully retract motor plate adjusting bolts.
4. Loosen the two rear (nearest the evaporator coil) motor
plate nuts.
5. Remove the two front motor plate nuts and carriage bolts.
6. Slide motor plate to the rear (toward the coil) and remove fan belt(s).
7. Slide motor plate to the front and hand tighten one of
the rear motor plate nuts (tight enough to prevent the
motor plate from sliding back but loose enough to allow
the plate to pivot upward).
8. Pivot the front of the motor plate upward enough to allow access to the motor mounting hex bolts and secure
in place by inserting a prop.
9. Remove the nuts from the motor mounting hex bolts and
remove motor.
10. Reverse above steps to install new motor.

Condenser-Fan Adjustment
1.
2.
3.
4.

Shut off unit power supply.
Remove fan guard.
Loosen fan hub setscrews.
Adjust fan height on shaft using a straightedge placed across
venturi and measure per Fig. 51.
5. Fill hub recess with permagum if rubber hubcap is
missing.
6. Tighten setscrews and replace panel(s).
7. Turn on unit power.

Fig. 49 — Evaporator-Fan Alignment and
Adjustment

Thermostatic Expansion Valve (TXV) — Each circuit has a TXV. The TXV is nonadjustable and is factory set
to maintain 10 to 13° F superheat leaving the evaporator coil.
The TXV controls flow of liquid refrigerant to the evaporator coils.

Power Failure — The economizer damper motor is a
spring return design. In event of power failure, dampers will
return to fully closed position until power is restored.

Gas Valve Adjustment

Refrigerant Charge — Amount of refrigerant charge

NATURAL GAS — The 2-stage gas valve opens and closes
in response to the thermostat or limit control.
When power is supplied to valve terminals 3 and 4, the
pilot valve opens to the preset position. When power is supplied to terminals 1 and 2, the main valve opens to its preset
position.
The regular factory setting is stamped on the valve body
(3.5 in. wg).
To adjust regulator:
1. Set thermostat at setting for no call for heat.
2. Turn main gas valve to OFF position.
3. Remove 1⁄8-in. pipe plug from manifold. Install a water
manometer pressure-measuring device.
4. Set main gas valve to ON position.
5. Set thermostat at setting to call for heat.
6. Remove screw cap covering regulator adjustment screw
(See Fig. 54).
7. Turn adjustment screw clockwise to increase pressure or
counterclockwise to decrease pressure.
8. Once desired pressure is established, set thermostat setting for no call for heat, turn off main gas valve, remove
pressure-measuring device and replace 1⁄8-in. pipe plug
and screw cap.

is listed on unit nameplate and in Table 1. Refer to Carrier
GTAC II; Module 5; Charging, Recovery, Recycling, and
Reclamation section for charging methods and procedures.
Unit panels must be in place when unit is operating during charging procedure.
NOTE: Do not use recycled refrigerant as it may contain
contaminants.
NO CHARGE — Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of
refrigerant (refer to Table 1).
LOW CHARGE COOLING — Using appropriate cooling
charging chart (see Fig. 52 and 53), add or remove refrigerant until conditions of the appropriate chart are met. Note
that charging chart is different from those normally used. An
accurate pressure gage and temperature sensing device are
required. Measure liquid line pressure at the liquid line service valve using pressure gage. Connect temperature sensing
device to the liquid line near the liquid line service valve
and insulate it so that outdoor ambient temperature does not
affect reading.
Using the above temperature and pressure readings, find
the intersect point on the appropriate cooling charging chart.
If intersection point on chart is above line, add refrigerant.
If intersection point on chart is below line, carefully reclaim
some of the charge. Recheck suction pressure as charge is
adjusted.
NOTE: Indoor-air cfm must be within normal operating range
of unit. All outdoor fans must be operating.
47

Fig. 50 — Belt Tension Adjustment

Fig. 53 — Cooling Charging Chart,
48EJ,EK,EW,EY038-048

Fig. 51 — Condenser-Fan Adjustment

Main Burners — For all applications, main burners are
factory set and should require no adjustment.
MAIN BURNER REMOVAL (Fig. 55)
1. Shut off (field-supplied) manual main gas valve.
2. Shut off power to unit.
3. Remove heating access panel.
4. Disconnect gas piping from gas valve inlet.
5. Remove wires from gas valve.
6. Remove wires from rollout switch.
7. Remove sensor wire and ignitor cable from IGC board.
8. Remove 2 screws securing manifold bracket to basepan.
9. Remove 4 screws that hold the burner support plate flange
to the vestibule plate.
10. Lift burner assembly out of unit.
11. Reverse procedure to re-install burners.

Filter Drier — Replace whenever refrigerant system is
exposed to atmosphere.

Protective Devices
COMPRESSOR PROTECTION
Overcurrent — Each compressor has one manual reset, calibrated trip, magnetic circuit breaker. Do not bypass connections or increase the size of the circuit breaker to correct trouble.
Determine the cause and correct it before resetting the breaker.
Overtemperature — Each 06D type compressor (024-038 units)
has an internal protector to protect it against excessively high
discharge gas temperatures.

Fig. 52 — Cooling Charging Chart,
48EJ,EK,EW,EY024-034
48

Crankcase Heater — Each compressor has a crankcase heater
to prevent absorption of liquid refrigerant by oil in the crankcase when the compressor is idle. Since power for the crankcase heaters is drawn from the unit incoming power, main
unit power must be on for the heaters to be energized.

Compressor Lockout Logic — If any of the safeties trip, the circuit will automatically reset (providing the
safety has reset) and restart the compressor in 15 minutes. If
any of the safeties trip 3 times within a 90-minute period,
then the circuit will be locked out and will require manual
resetting by turning off either the unit disconnect or the control circuit breaker, or opening the thermostat.

IMPORTANT: After a prolonged shutdown or service job, energize the crankcase heaters for 24 hours
before starting the compressors.

Replacement Parts — A complete list of replacement
parts may be obtained from any Carrier distributor upon
request.

EVAPORATOR FAN MOTOR PROTECTION — A manual
reset, calibrated trip, magnetic circuit breaker protects against
overcurrent. Do not bypass connections or increase the size
of the breaker to correct trouble. Determine the cause and
correct it before resetting the breaker. If the evaporator-fan
motor is replaced with a different horsepower motor, resizing of the circuit breaker is required. Contact Carrier
Application Engineering.
CONDENSER-FAN MOTOR PROTECTION — Each
condenser-fan motor is internally protected against
overtemperature.
HIGH- AND LOW-PRESSURE SWITCHES — If either
switch trips, or if the compressor overtemperature switch activates, that refrigerant circuit will be automatically stopped.
See Compressor Lockout Logic section on this page.
FREEZE PROTECTION THERMOSTAT (FPT) — Freeze
protection thermostats are located on the evaporator coil for
each circuit. One is located at the top and bottom of each
circuit. It detects frost build-up and turns off the compressor,
allowing the coil to clear. Once the frost has melted, the compressor can be reenergized.

Fig. 54 — Gas Valve

Relief Devices — All units have relief devices to protect against damage from excessive pressures (i.e., fire). These
devices are installed on the suction line, liquid line, and on
the compressor.
Power Circuit — A typical power wiring schematic is
shown in Fig. 56.

Control Circuit, 115-V — This control circuit is protected against overcurrent by a 5.0 amp circuit breaker (CB3).
Breaker can be reset. If it trips, determine cause of trouble
before resetting. A typical 115-v control wiring schematic is
shown in Fig. 57 and 58.
Control Circuit, 24-V — This control circuit is protected against overcurrent by a 3.2 amp circuit breaker (CB4).
Breaker can be reset. If it trips, determine cause of trouble
before resetting. A typical 24-v control wiring schematic is
shown in Fig. 59 and 60.

Fig. 55 — Main Burner Removal

LEGEND and NOTES for Fig. 56-60 — Typical Wiring Schematics
LEGEND
AHA
BP
BR
C
CAP
CB
CC
CCB
CCH
COM
COMP
CR
DM
DP
EC
EQUIP
FLA
FPT
FU
GRD
GVR
HPS
HS
HV
IDM

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

Adjustable Heat Anticipator
Building Pressure
Burner Relay
Contactor, Compressor
Capacitor
Circuit Breaker
Cooling Compensator
Controller Circuit Breaker
Crankcase Heater
Communication
Compressor Motor
Control Relay
Damper Motor
Duct Pressure
Enthalpy Control
Equipment
Full Load Amps
Freeze Protection Thermostat
Fuse
Ground
Gas Valve Relay
High-Pressure Switch
Hall Effect Sensor
High Voltage
Induced-Draft Motor

IFC
IFCB
IFM
IFR
IGC
IP
L
LPS
MGV
NC
NO
OAT
OFC
OFM
PEC
PEM
PES
PESC

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

PL
R
RAT
RS
SAT
TB

—
—
—
—
—
—

Indoor Fan Contactor
Indoor Fan Circuit Breaker
Indoor-Fan Motor
Indoor-Fan Relay
Integrated Gas Unit Controller
Internal Protector
Light
Low-Pressure Switch
Main Gas Valve
Normally Closed
Normally Open
Outdoor-Air Thermistor
Outdoor-Fan Contactor
Outdoor-Fan Motor
Power Exhaust Contactor
Power Exhaust Motor
Power Exhaust Sequencer
Power Exhaust Sequencer
Controller
Plug Assembly
Relay
Return-Air Thermistor
Rollout Switch
Supply-Air Thermistor
Terminal Block

TC
TH
TRAN
UL
VFD

—
—
—
—
—

Thermostat Cooling
Thermostat Heating
Transformer
Compressor Unloader
Variable Frequency Drive
Terminal (Marked)
Terminal (Unmarked)
Terminal Block
Splice
Factory Wiring
Field Wiring
To Indicate Common Potential Only,
Not To Represent Wiring

NOTES:
1. Connect TRAN1 to H4 for 460 v units. Connect to H3 for 230 v. If
208/230 v units are run with a 208 v power supply connect to H2.
2. Connect TRAN2 to black lead for 460 v units. Connect to orange
lead for 230 v units. If 208/230 v units are run with a 208 v power
supply connect to red lead.
3. Circuit breaker must trip amps are equal to or less than 156% FLA
for CB1 and CB2. All others are 140%.
4. If any of the original wire furnished must be replaced, it must be
replaced with type 90 C wire or its equivalent.
5. Compressors and/or fan motors are thermally protected.
6. Three phase motors are protected against primary single phasing
conditions.
7. Red wire and violet wire are spliced together at the factory. The
brown wire has a wire nut added at the factory.
TABLE A
THE FOLLOWING COMPRESSORS HAVE
TWO PARALLEL WIRES RUN FROM TB1
TO THE COMPRESSORS
(NOT SHOWN ON LABEL DIAGRAM)
COMPRESSOR VOLTAGE
WIRE
MODEL
QUANTITY
06D-537
208/230-3-60
2

TABLE B
THE FOLLOWING FAN MOTORS HAVE TWO
PARALLEL WIRES RUN FROM TB1 TO THE
FAN MOTORS
(NOT SHOWN ON LABEL DIAGRAM)
INDOOR
WIRE
VOLTAGE
MOTOR
QUANTITY
20 HP
208/230-3-60
2

51
Fig. 56 — Typical Power Schematic; 48EJ,EK,EW,EY024-034; 208/230-3-60 and 460-3-60

52
Fig. 57 — Typical VAV 115-v Control Circuit

53
Fig. 58 — Typical CV 115-v Control Circuit

54
Fig. 59 — Typical VAV 24-v Control Circuit

55
Fig. 60 — Typical CV 24-v Control Circuit

TROUBLESHOOTING
Typical refrigerant circuiting diagrams are shown in Fig. 61-63. An algorithm diagram of the IGC (Integrated Gas Unit Controller) control is shown in Fig. 64.

LEGEND
FPS — Freeze Protection Switch
HPS — High-Pressure Switch
LPS — Low-Pressure Switch

Fig. 61 — Typical Refrigerant Circuiting (48EJ,EK,EW,EY024-034)

LEGEND
FPS — Freeze Protection Switch
HPS — High-Pressure Switch
LPS — Low-Pressure Switch

Fig. 62 — Typical Refrigerant Circuiting (48EJ,EK,EW,EY038,044)

LEGEND
FPS — Freeze Protection Switch
HPS — High-Pressure Switch
LPS — Low-Pressure Switch

Fig. 63 — Typical Refrigerant Circuiting (48EJ,EK,EW,EY048)

LEGEND
IDM — Induced-Draft Motor
IGC — Integrated Gas Unit Controller

NOTE: Thermostat Fan Switch in the ‘‘AUTO’’ position or sensor-equipped unit.

Fig. 64 — IGC Control (Heating and Cooling)

The alarm codes for the IGC control board are shown in
Table 22.

Diagnostic LEDs — There are 3 LEDs (red, yellow,
and green) on the lower right hand side of the control board.
The red light is used to check unit operation and alarms. A
constant pulse is normal unit operation. A series of quick
blinks indicates an alarm. Refer to Table 23 below for a description of alarms. The yellow LED blinks during transmission with the CCN (Carrier Comfort Network). The green
LED blinks during transmission with the expansion board.

Table 22 — IGC Control Board LED Alarms
INDICATION
ON
OFF
1 FLASH
2 FLASHES
3 FLASHES
4 FLASHES
5 FLASHES
6 FLASHES
7 FLASHES
8 FLASHES

ERROR MODE
Normal Operation
Hardware Failure
Fan ON/OFF Delay Modified
Limit Switch Fault
Flame Sense Fault
4 Consecutive Limit Switch Faults
Ignition Lockout Fault
Induced Draft Motor Fault
Rollout Switch Fault
Internal Control Fault

Table 23 — Control Board LED Alarms
LED Blinks

Error Code

Description

—

HF-13

Compressor 1 Safety

HF-14

Compressor 2 Safety

HF-15

Thermostat Failure

HF-05

SAT Thermistor Failure

HF-06

OAT Thermistor Failure

HF-03

Space Temp. Sen. Failure

HF-12

RAT Thermistor Failure

SE-05

Loss of Communications
with Expansion Board

HF-16

Control Board Failure

HF-17

Expansion Board Failure

Normal Operation

Troubleshooting Comments
The expansion board and control board flash the red LED in one-second
intervals when the board is operating properly.
The high or low pressure safety switch for compressor no. 1 has opened for
3 seconds. The error will be cleared and compressor no. 1 will be allowed
to turn on in 15 minutes. If the safeties have been tripped 3 times in 90 minutes, compressor no. 1 will be locked out until the control board has been
manually reset.
The high or low pressure safety switch for compressor no. 2 has opened for
3 seconds. The error will be cleared and compressor no. 2 will be allowed
to turn on in 15 minutes. If the safeties have been tripped 3 times in 90 minutes, compressor no. 2 will be locked out until the control board has been
manually reset.
The thermostat is calling for both heating and cooling at the same time. The
unit will operate on a first call basis and will automatically reset.
The supply-air temperature (SAT) sensor has failed. First check for wiring
errors, then replace sensor.
The outside air temperature (OAT) sensor has failed. First check for wiring
errors, then replace sensor.
The space temperature sensor has failed. First check for wiring errors, then
replace sensor.
The return-air temperature (RAT) sensor has failed. Ensure that the unit is
a VAV unit. If NOT a VAV unit set DIP switch position 1 to the closed position
and reset power. Then check for wiring errors. Finally, replace sensor.
Communications between the expansion board and the control board have
been interrupted. Ensure that an expansion board is installed and wired using the wire harness supplied with the expansion module. If an expansion
board is not used ensure that DIP switch position 3 is in the closed position,
and reset power.
Generated when hardware has failed on control board. Replace the control
board.
Generated when hardware has failed on the expansion board. Replace the
expansion board.

DIP — Dual In-Line Package
VAV — Variable Air Volume

Tables 24-26 show the input and output channel
designations.
Table 24 — I/O Channel Designations Base Module — CV
TERMINAL NO.
T1-2
T3-4
T5-6
T7-8
T9-10
T11-12
T13-14
T15-16
T17-25
T18-25
T19-25
T20-25
T21-25
T22-25

ASSIGNMENT
TERMINAL NO.
SPT (CCN) — 10KV Thermistor
T23-25
STO (CCN) — 10KV Thermistor
T24-25
OAT — 5KV Thermistor
T26-27
SAT — 5KV Thermistor
T28-29
—
T30-29
SAT Reset — AI (4 to 20 mA)
T31-32
—
T33-32
—
T34-35
Y1 or Remote Start/Stop — DI (24 vac)
T36-35
Y2 — DI (24 vac)
T37-38
W1 — DI (24 vac)
T39-38
W2 — DI (24 vac)
K1
G — DI (24 vac)
K2
Compressor 1 Safety — DI (24 vac)
K3

ASSIGNMENT
Compressor 2 Safety — DI (24 vac)
Outside Air Enthalpy — DI (24 vac)
Economizer Pos. — AO (4-20 mA)
Heat 1 Relay — DO (24 vac)
Heat 2 Relay — DO (24 vac)
CV Power Exhaust 1/Modulating Power Exhaust — DO (115 vac)
CV Power Exhaust 2 — DO (115 vac)
Condenser Fan — DO (115 vac)
OFC2 — DO (115 vac)
—
—
Indoor Fan Relay — DO (LV)
Compr. 1 — DO (HV)
Compr. 2 — DO (HV)

Table 25 — I/O Channel Designations Base Module — VAV
TERMINAL NO.
T1-2
T3-4
T5-6
T7-8
T9-10
T11-12
T13-14
T15-16
T17-25
T18-25
T19-25
T20-25
T21-25
T22-25

ASSIGNMENT
SPT (CCN) — 10KV Thermistor
RAT — 5KV Thermistor
OAT — 5KV Thermistor
SAT — 5KV Thermistor
—
SAT Reset — AI (4 to 20 mA)
—
—
Remote Start/Stop — DI (24 vac)
—
—
—
—
Compressor 1 Safety — DI (24 vac)

TERMINAL NO.
T23-25
T24-25
T26-27
T28-29
T30-29
T31-32
T33-32
T34-35
T36-35
T37-38
T39-38
K1
K2
K3

ASSIGNMENT
Compressor 2 Safety — DI (24 vac)
Outside Air Enthalpy — DI (24 vac)
Economizer Pos. — AO (4-20 mA)
Heat 1 Relay − DO (24 vac)
Heat Interlock Relay — DO (24 vac)
Modulated Power Exhaust — DO (115 vac)
—
Condenser Fan — DO (115 vac)
OFC2 — DO (115 vac)
Unloader 1 — DO (115 vac)
Unloader 2 — DO (115 vac)
Indoor Fan Relay — DO (LV)
Compr. 1 (HV)
Compr. 2 — DO (HV)

Table 26 — I/O Channel Designations Expansion Module (Field-Installed) — CV and VAV
TERMINAL NO.
T1-2
T3-4
T5-6
T7-8
T9-10
T11-12
T13-14
T15-16
T17-25
T18-25
T19-25
T20-25
T21-25
T22-25

ASSIGNMENT
—
—
—
—
—
IAQ Indoor — AI (4 to 20 mA)
IAQ Outdoor — AI (4 to 20 mA)
—
Fan Status — DI (24 vac)
Filter Status − DI (24 vac)
Field Applied Status — DI (24 vac)
Demand Limit — DI (24 vac)
Fire — Unit Shutdown — DI (24 vac)
Fire — Pressurization — DI (24 vac)

TERMINAL NO.
T23-25
T24-25
T26-27
T28-29
T30-29
T31-32
T33-32
T34-35
T36-35
T37-38
T39-38
K1
K2
K3

LEGEND (Tables 24-26)
AI
— Analog Input
AO — Analog Output
CCN — Carrier Comfort Network
CV
— Constant Volume
DI
— Direct Input
DO — Direct Output
HV
— High Voltage
IAQ — Indoor Air Quality

KV
LV
OAT
OFC
RAT
SAT
SPT
STO
T
VAV

—
—
—
—
—
—
—
—
—
—

ASSIGNMENT
Fire — Evacuation — DI (24 vac)
Fire — Smoke Purge — DI (24 vac)
—
—
Alarm Light Indicator — DO (24 vac)
Power Exhaust Fire No. 1 — DO (115
Power Exhaust Fire No. 2 — DO (115
Power Exhaust Fire No. 3 — DO (115
Power Exhaust Fire No. 4 — DO (115
—
—
—
—
—

vac)
vac)
vac)
vac)

Kilo-Ohms
Low Voltage
Outdoor-Air Temperature
Outdoor Fan Contactor
Return-Air Temperature
Supply-Air Temperature
Space Temperature
Space Temperature Offset
Terminal
Variable Air Volume

NOTE: For 4 to 20 mA signals, all even numbered terminals are negative (−) polarity, and all odd numbered terminals are positive (+) polarity.

PACKAGED SERVICE TRAINING
Our packaged service training programs provide an excellent way to increase your knowledge of the
equipment discussed in this manual. Product programs cover:
• Unit Familiarization
• Maintenance
• Installation Overview
• Operating Sequence
A large selection of product, theory, and skills programs is available. All programs include a video
cassette and/or slides and a companion booklet. Use these for self teaching or to conduct full training
sessions.
For a free Service Training Material Catalog (STM), call 1-800-962-9212. Ordering instructions are
included.

Copyright 1997 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
PC 111
Catalog No. 564-962
Printed in U.S.A.
Form 48E-5SI
Pg 62
8-97
Replaces: 48E-3SI
Tab 1a

START-UP CHECKLIST
MODEL NO.:

SERIAL NO.:

SOFTWARE VERSION (SEE FIG. 16)

TECHNICIAN:

DATE:

PRE-START-UP:
M VERIFY THAT DIP SWITCH SETTINGS ARE CORRECT
M VERIFY THAT ALL PACKING MATERIALS HAVE BEEN REMOVED FROM UNIT
M REMOVE ALL SHIPPING HOLDDOWN BOLTS AND BRACKETS PER INSTRUCTIONS
M VERIFY INSTALLATION OF ECONOMIZER HOOD
M VERIFY INSTALLATION OF ALL OPTIONS AND ACCESSORIES
M VERIFY THAT CONDENSATE CONNECTION IS INSTALLED PER INSTRUCTIONS
M VERIFY THAT ALL ELECTRICAL CONNECTIONS AND TERMINALS ARE TIGHT
M CHECK GAS PIPING FOR LEAKS
M CHECK THAT INDOOR-AIR FILTERS ARE CLEAN AND IN PLACE
M VERIFY THAT UNIT IS LEVEL WITHIN TOLERANCES
M CHECK FAN WHEELS AND PROPELLERS FOR LOCATION IN HOUSING/ORIFICE, AND VERIFY SETSCREW
IS TIGHT
M VERIFY THAT FAN SHEAVES ARE ALIGNED AND BELTS ARE PROPERLY TENSIONED
M VERIFY THAT SUCTION, DISCHARGE, AND LIQUID SERVICE VALVES ON EACH CIRCUIT ARE OPEN

START-UP
ELECTRICAL
SUPPLY VOLTAGE

L1-L2

L2-L3

L3-L1

COMPRESSOR AMPS — COMPRESSOR NO. 1

— COMPRESSOR NO. 2

SUPPLY FAN AMPS (CV)
(VAV)

EXHAUST FAN AMPS
*

*VAV fan supply amps reading must be taken with a true RMS meter for accurate readings.
M ADJUST VARIABLE FREQUENCY DRIVE (VFD) TO APPLICATION REQUIREMENTS.
TEMPERATURES
OUTDOOR-AIR TEMPERATURE

F DB (Dry Bulb)

RETURN-AIR TEMPERATURE

F DB

COOLING SUPPLY AIR

GAS HEAT SUPPLY AIR

WB (Wet Bulb)

PRESSURES
IN. WG

GAS INLET PRESSURE

IN. WG

STAGE NO. 2

IN. WG

GAS MANIFOLD PRESSURE

STAGE NO. 1

REFRIGERANT SUCTION

CIRCUIT NO. 1

PSIG

CIRCUIT NO. 2

PSIG

REFRIGERANT DISCHARGE

CIRCUIT NO. 1

PSIG

CIRCUIT NO. 2

PSIG

M VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS ON PAGE 48
CL-1

HIGH PRESSURE SWITCH SETTING

psig

LOW PRESSURE SWITCH SETTING

psig

MOTOR PULLEY PART NUMBER
FAN PULLEY PART NUMBER
BELT PART NUMBER
BELT SIZE

in.

FILTER QUANTITY
FILTER SIZES

in.

ADDITIONAL NOTES:
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________
_______________________________________________________________________________________________________

CUT ALONG DOTTED LINE

M ENSURE DRIVES OPERATE WITHIN LIMITS OF FAN PERFORMANCE TABLES

CUT ALONG DOTTED LINE

M SET ECONOMIZER MINIMUM VENT POSITION TO JOB REQUIREMENTS

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

GENERAL

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.5
Linearized                      : Yes
XMP Toolkit                     : 3.1-701
Create Date                     : 1997:09:16 09:30:24Z
Modify Date                     : 2005:11:11 18:38:15-05:00
Metadata Date                   : 2005:11:11 18:38:15-05:00
Producer                        : Acrobat Distiller 3.0 for Windows
Keywords                        : 
Format                          : application/pdf
Title                           : 
Description                     : 
Creator                         : Carrier Corporation
Subject                         : 
Document ID                     : uuid:d3ffff0c-462d-4eef-8e06-5fae18a35aee
Instance ID                     : uuid:cc7dc27c-6712-4e41-93f1-f4c3cbac2562
Page Count                      : 64
Author                          : Carrier Corporation

EXIF Metadata provided by EXIF.tools

Carrier Single Package Rooftop Units Electric Cooling Gas Heating 48Ej Users Manual

48EJ to the manual b9a43d94-fd73-49a9-aa7f-83f77933caab

Navigation menu

Versions of this User Manual:

Views

Navigation