Carrier 38Ah044 084 Users Manual

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38AH044-134
Air-Cooled Condensing Units
50/60 Hz

Installation, Start-Up and
Service Instructions
CONTENTS

Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . 1
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37
Step 1 — Rig and Place Unit . . . . . . . . . . . . . . . 1
• DOMESTIC UNITS
• EXPORT UNITS
• PLACING UNITS
Step 2 — Check Compressor Mounting . . . . . 3
• UNITS 38AH044-084
• UNITS 38AH094-134
Step 3 — Make Refrigerant Piping
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
• UNITS 38AH044-084
• UNITS 38AH094-134
Step 4 — Make Electrical Connections . . . . . . 23
• POWER SUPPLY
• FIELD POWER CONNECTIONS
• MAIN POWER
• CONTROL CIRCUIT WIRING
Step 5 — Install Accessories . . . . . . . . . . . . . . . 37
• LOW-AMBIENT OPERATION
• MISCELLANEOUS ACCESSORIES
PRE-START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . 37,38
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-45
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46-49
CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49-52
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . 53,54
START-UP CHECKLIST . . . . . . . . . . . . . . . CL-1, CL-2

SAFETY CONSIDERATIONS
Installing, starting up, and servicing this equipment can
be hazardous due to system pressures, electrical components, and equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service mechanics
should install, start up, and service this equipment.
Untrained personnel can perform basic maintenance functions, such as cleaning coils. All other operations should be
performed by trained service personnel.
When working on the equipment, observe precautions in
the literature, and on tags, stickers, and labels attached to the
equipment and any other safety precautions that may apply.
• Follow all safety codes.
• Wear safety glasses and work gloves.
• Use care in handling, rigging, and setting bulky
equipment.

INSTALLATION
Step 1 — Rig and Place Unit — All units are
designed for overhead rigging, and it is important that this
method be used. Lifting holes are provided in the frame base
rails, which are marked for rigging (see rigging label on the
unit and Tables 1, 2A, and 2B for rigging weights and center
of gravity). It is recommended that field-supplied pipes, of
sufficient length to extend at least 12-in. (305 mm) beyond
the frame, be passed through the holes.
To maintain unit stability while lifting, use 4 cables,
chains, or straps of equal length. Attach one end of
each cable to one pipe end and the other end of each
cable to the overhead rigging point.
Use spreader bars or frame to keep the cables, chains,
and straps clear of the unit sides. Leave standard coil protection packaging in place during rigging to provide protection to coils. Remove and discard all coil protection after
rigging cables are detached.
DOMESTIC UNITS — For units 38AH044-084, 124, and
134; standard unit packaging consists of coil protection only.
There is no standard packaging provided for units 38AH094
and 104. Skids are not provided. If overhead rigging is not
available at the jobsite, place the unit on a skid or pad before
dragging or rolling. When rolling, use a minimum of
3 rollers. When dragging, pull the pad or skid. Do not apply
force to the unit. When in final position, raise from above to
lift unit off the pad or skid.
EXPORT UNITS — All export units are mounted on skids
with vertical coil protection. Leave the unit on the skid until
it is in final position. While on the skid, the unit can be rolled
or skidded. Apply force to the skid, not to the unit. Use a
minimum of 3 rollers when rolling. When in final position,
raise from above to remove the skid.
PLACING UNITS
Units 38AH044-084 — Refer to Fig. 1 and 2 for airflow clearances. Recommended minimum clearances are 6 ft (1829 mm)
for unrestricted airflow and service on sides of unit, 5 ft
(1524 mm) on ends, and unrestricted clear air space above
the unit. Provide ample space to connect liquid and suction
lines to indoor unit. For multiple units, allow 8 ft (2440 mm)
separation between units for airflow and service.

Do not forklift these units unless the unit is attached to
a skid designed for forklifting.

ELECTRIC SHOCK HAZARD.
Open all remote disconnects before servicing
this equipment.

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. 563-704
Printed in U.S.A.
Form 38AH-15SI
Pg 1
10-98
Replaces: 38AH-14SI
Tab 3a

The placement area must be level and strong enough to
support the operating weight of the unit (see Table 3A or
3B). When unit is in proper location, use of mounting holes
in base rails is recommended for securing unit to supporting
structure. For mounting unit on vibration isolators, a perimeter support channel between the unit and the isolators is
recommended. Fasteners for mounting unit are field supplied. Be sure to mount unit level to ensure proper oil return
to compressors.
Units 38AH094-134 — Refer to Fig. 3-6 for airflow
clearances. Recommended minimum clearances are 6 ft
(1829 mm) for unrestricted airflow and service on sides of
unit, 5 ft (1524 mm) on ends, and unrestricted clear air space
above unit. Provide ample space to connect liquid and suction lines to indoor unit. For multiple units, allow
8 ft (2440 mm) separation between units for airflow and
service.

support units on individual isolation supports. Support channel, hardware, and fasteners are field supplied. When unit is
in proper location, level unit and bolt into position with fieldsupplied bolts.
Units 38AH124,134 — For ease of shipment and handling,
unit 38AH124 is shipped as 2 modules (124A and 124B)
and unit 38AH134 is shipped as 2 modules (134A and 134B).
The modules must be connected at the final installation site
with the factory-shipped piping and sheet metal trim kit mounted
on Module 124A or 134A. See Fig. 7.

Do not move assembled 38AH124 or 134 units as a single
assembly. Always move modules individually during installation or at any other time.
Mark installation site for placement of Modules 124A and
124B or Modules 134A and 134B. See Table 4A or 4B for
final assembled dimensions. A service space of 24 in.
(610 mm) is required between the 2 modules for piping and
sheet metal trim installation.
Place Module 124A or 134A in position, ensuring that the
control box is at the end opposite the service space. See
Fig. 8.
Remove sheet metal and tubing from Module 124A or 134A
sheet metal trim kit (Fig. 7). Remove sheet metal cover panels from return-bend end of unit facing the service space.
See Fig. 8. These panels may be discarded or saved for
reinstallation if module is moved from site. See Fig. 9.

Do not forklift these units unless the unit is attached to
a skid designed for forklifting.
The placement area must be level and strong enough to
support the operating weight of the unit. See Table 4A
or 4B. Refer to the following paragraphs for the proper placement of the unit.
Units 38AH094,104 — For mounting units on vibration isolators, a perimeter support channel is required between the
unit and the support isolators. The perimeter support channel must be sized to support the fully assembled unit. Do not

Table 1 — Rigging Center of Gravity — in. (mm)
UNIT
38AH
Dimension
Dimension
Dimension
Dimension
Dimension
Dimension
Dimension
Dimension

044
X
Y
X-C
Y-C
K
L
K-C
L-C

49
39
49
39

(1232)
(984)
(1234)
(993)
—
—
—
—

054

064

48 (1224)
39 (978)
48 (1229)
39 (991)
—
—
—
—

50 (1260)
38 (968)
50 (1261)
39 (986)
—
—
—
—

074
57
39
56
40

(1443)
(993)
(1425)
(1006)
—
—
—
—

084
57
39
56
40

(1448)
(991)
(1422)
(1008)
—
—
—
—

094
66
31
66
31

(1676)
(787)
(1676)
(787)
—
—
—
—

104
63
34
63
34

(1600)
(851)
(1600)
(851)
—
—
—
—

MODULE
124A
50 (1260)
38 (968)
50 (1260)
39 (986)
—
—
—
—

MODULE
124B
—
—
—
—
50 (1260)
38 (968)
50 (1260)
39 (986)

LEGEND
— — Not Applicable
C — Copper Fin Coils

124, 134 ONLY

TOP VIEW, TYPICAL

2

MODULE
134A
50 (1260)
38 (968)
50 (1260)
39 (986)
—
—
—
—

MODULE
134B
—
—
—
—
57 (1443)
39 (993)
56 (1425)
40 (1006)

Remove sheet metal cover panels from return-bend end of
Module 124B or 134B. Place Module 124B or 134B in
position. The exposed return-bend ends of each module are
now opposite each other and facing the service space. The
compressors of each module are on opposite sides of the unit.

Step 2 — Check Compressor Mounting
UNITS 38AH044-084 — Compressors are mounted on pans
and are held down by 4 bolts during shipment. After unit is
installed, loosen each of these bolts until the snubber washer
can be moved with finger pressure. See Fig. 10.

IMPORTANT: Modules must be placed 24 in.
(610 mm) apart and square relative to each other.

UNITS 38AH094-134 — Units 38AH094 and 104 compressors are mounted on rails and held down by rail bolts during
shipment. After unit is installed, loosen the rail bolts to allow the rails and compressors to float freely on the springs
located under the rails. See Fig. 10.
Units 38AH124 and 134 compressors are mounted on pans
and are held down by 4 bolts during shipment. After unit is
installed, loosen each of these bolts until snubber washer can
be moved with finger pressure. See Fig. 10.

The modules are now in position for piping installation and final assembly. See Fig. 8. For mounting units on
vibration isolators, a perimeter support channel is required
between the assembled unit and the support isolators. The
perimeter support channel must be sized to support the fully
assembled unit. Do not support modules on individual isolation supports. Support channel, hardware, and fasteners are
field supplied.
When unit is in proper location, level unit and bolt into
position with field-supplied bolts.

Table 2B — Operational Corner Weights with
Refrigerant Charge (Approximate) — Kg

Table 2A — Operational Corner Weights with
Refrigerant Charge (Approximate) — Lb
UNIT
38AH
044
044C
054
054C
064
064C
074
074C
084
084C
094
094C
104
104C
MODULE
38AH
124A
124A-C
124B
124B-C
134A
134A-C
134B
134B-C

3259
3547
3309
3597
3565
3998
3812
4229
4057
4735
5088
5813
5435
6160

OPERATIONAL CORNER WEIGHT
A
B
C
D
939
893
695
732
1013
967
765
802
964
905
697
742
1034
978
771
814
1018
1011
765
771
1125
1117
874
879
1146
986
777
903
1272
1059
862
1035
1220
1049
827
961
1425
1186
965
1159
1114
2192
1182
601
1273
2504
1350
686
1240
2138
1302
755
1405
2423
1476
856

3630
4063
3630
4063
3630
4063
3877
4294

1037
1144
1037
1144
1037
1144
1167
1293

TOTAL
WEIGHT

1030
1137
1030
1137
1030
1137
997
1080

779
889
779
889
779
889
789
874

UNIT
38AH
044
044C
054
054C
064
064C
074
074C
084
084C
094
094C
104
104C
MODULE
38AH
124A
124A-C
124B
124B-C
134A
134A-C
134B
134B-C

785
894
785
894
785
894
924
1047

LEGEND
C — Copper Fin Coils
NOTE: Total weight may differ from summation of corner weights due
to rounding of numerals.

1478
1609
1501
1632
1617
1813
1729
1918
1840
2148
2308
2637
2465
2794

OPERATIONAL CORNER WEIGHT
A
B
C
D
426
405
316
332
460
438
347
364
437
411
316
337
469
444
350
369
462
459
347
350
510
508
397
399
520
447
352
410
577
481
391
470
553
476
375
436
646
538
438
526
505
994
536
272
577
1136
612
311
562
970
591
342
637
1099
670
388

1647
1843
1647
1843
1647
1843
1759
1948

470
519
470
519
470
519
529
587

TOTAL
WEIGHT

467
516
467
516
467
516
452
490

353
403
353
403
353
403
358
396

356
405
356
405
356
405
419
475

LEGEND
C — Copper Fin Coils
NOTE: Total weight may differ from summation of corner weights due
to rounding of numerals.

TOP VIEW, TYPICAL

3

DUAL CKT

SINGLE CKT

21⁄89 Dia [54 mm]

25⁄89 Dia [67 mm]

SUCTION
CONNECTION(S)
LIQUID
CONNECTION(S)
SUCTION C
LIQUID D
SUCTION (Ckt A)
SUCTION (Ckt B)

⁄ 9 Dia [22 mm]

11⁄89 Dia [29 mm]

28-11⁄169 [627mm]
18-101⁄169 [561mm]
18-713⁄169 [503mm]
28-5⁄89
[626mm]

18-105⁄169 [567mm]
18-105⁄169 [567mm]
28-5⁄89
[626mm]

LIQUID (Ckt A)
LIQUID (Ckt B)

28-53⁄49 [756mm]
28-105⁄89 [879mm]

78

—
28-105⁄89 [879mm]
—

Chart 1, Field Power Supply Connections
UNIT
044
044, 054
044, 054, 064
064

VOLTAGE
230
208/230
346, 380/415
460,575,380
208/230
346, 380/415

Hz
50
60
50
60
60
50

DIAMETER — in. [mm]
35⁄8 [92]
35⁄8 [92]
21⁄2 [63]
21⁄2 [63]
21⁄2 [63]
35⁄8 [92]

QTY
1
1
1
1
2
1

LEGEND
C
— Copper Fin Coils
MTG — Mounting
SAE — Society of Automotive Engineers

NOTES:
1. The approximate operating weight of the unit is:
38AH-044--3259 lb [1478 kg]
38AH-044--C
3547 lb [1609 kg]
38AH-054--3309 lb [1501 kg]
38AH-054--C
3597 lb [1632 kg]
38AH-064--3565 lb [1617 kg]
38AH-064--C
3998 lb [1813 kg]
2. Unit must have clearances for airflow as follows:
Top — Do not restrict in any way.
Ends — 5 ft [1524 mm]
Sides — 6 ft [1829 mm]
3. Mounting holes may be used to mount unit to concrete pad. They are not recommended for mounting
unit to spring isolators. If spring isolators are used, a perimeter support channel between the unit and
the isolators is recommended.
4. One 35⁄89 (92 mm) diameter hole is recommended for single-entry power on size 064 (208/230-v) units.
5. See Table 1 for rigging center of gravity (Dimensions X,Y). See Table 2A and 2B for A-D corner weights.
6. Circled numerals in Top View refer to condenser fans by position.

Fig. 1 — Dimensions — Units 38AH044,054,064
4

DUAL CKT

SINGLE CKT

21⁄89 Dia [54 mm]

25⁄89 Dia [67 mm]

SUCTION
CONNECTION(S)
LIQUID
CONNECTION(S)
SUCTION C
LIQUID D
SUCTION (Ckt A)
SUCTION (Ckt B)

⁄ 9 Dia [22 mm]

11⁄89 Dia [29 mm]

28-11⁄169 [627mm]
18-101⁄169 [561mm]
18-713⁄169 [503mm]
28-5⁄89
[626mm]

18-105⁄169 [567mm]
18-105⁄169 [567mm]
28-5⁄89
[626mm]

LIQUID (Ckt A)
LIQUID (Ckt B)

28-53⁄49 [756mm]
28-105⁄89 [879mm]

78

—
28-105⁄89 [879mm]
—

Chart 1, Field Power Supply Connections
UNIT
074

074, 084

084

VOLTAGE
208/230

Hz
60

460
346, 380/415
380
575
208/230
460

60
50
60
60
60
60

DIAMETER — in. [mm] QTY
21⁄2 [63]
2
1
21⁄2 [63]
1
35⁄8 [92]
1
35⁄8 [92]
1
21⁄2 [63]
2
35⁄8 [92]
35⁄8 [92]
1

LEGEND
C
— Copper Fin Coils
MTG — Mounting
SAE — Society of Automotive Engineers
NOTES:
1. The approximate operating weight of the unit is:
38AH-074--3812 lb (1729 kg)
38AH-074--C
4229 lb (1918 kg)
38AH-084--4057 lb (1840 kg)
38AH-084--C
4735 lb (2148 kg)
2. Unit must have clearances for airflow as follows:
Top — Do not restrict in any way.
Ends — 5 ft [1524 mm]
Sides — 6 ft [1829 mm]
3. Mounting holes may be used to mount unit to concrete pad. They are not recommended for mounting unit
to spring isolators. If spring isolators are used, a perimeter support channel between the unit and the isolators is recommended.
4. See Table 1 for rigging center of gravity (Dimensions X,Y). See Table 2A and 2B for A-D corner weights.
5. Circled numerals in Top View refer to condenser fans by position.

Fig. 2 — Dimensions — Units 38AH074,084

5

Chart 1, Field Power Supply Connections
UNIT
38AH

VOLTAGE

Hz

094

208/230
460, 575,
380
346, 380/415

50

DIAMETER — in. (mm)

QUANTITY

60

35⁄8 (92)

2

60

35⁄8 (92)

1

3 ⁄ (92)

1

58

LEGEND
C
— Copper Fin Coils
MTG — Mounting
SAE — Society of Automotive Engineers
NOTES:
1. The approximate operating weight of the unit is:
38AH-094--5088 lb (2308 kg)
38AH-094--C
5813 lb (2637 kg)
2. Unit must have clearances for airflow as follows:
Top — Do not restrict in any way.
Ends — 5 ft [1524 mm]
Sides — 6 ft [1829 mm]
3. Mounting holes may be used to mount unit to concrete pad. They are not
recommended for mounting unit to spring isolators.
4. Two 35⁄89 (92-mm) dia holes are recommended for parallel conductors on
208/230 v units.
5. Circled numerals in Top View refer to condenser fans by position.
6. If spring isolators are used, a perimeter support channel between the unit
and the isolators is recommended.
7. See Table 1 for rigging center of gravity (Dimensions X,Y). See Table 2A
and 2B for A-D corner weights.

Fig. 3 — Dimensions — Unit 38AH094
6

LEGEND
C
— Copper Fin Coils
MTG — Mounting
SAE — Society of Automotive Engineers

Chart 1, Field Power Supply Connections
UNIT
38AH

VOLTAGE

Hz

DIAMETER — in. (mm)

QUANTITY

60

35⁄8 (92)

2

104

208/230
460, 575,
380
346, 380/415

60

35⁄8 (92)

1

50

35⁄8 (92)

1

NOTES:
1. The approximate operating weight of the unit is:
38AH-104--5435 lb (2465 kg)
38AH-104--C
6160 lb (2794 kg)
2. Unit must have clearances for airflow as follows:
Top — Do not restrict in any way.
Ends — 5 ft [1524 mm]
Sides — 6 ft [1829 mm]
3. Mounting holes may be used to mount unit to concrete pad. They are not
recommended for mounting unit to spring isolators.
4. Two 35⁄89 (92-mm) dia holes are recommended for parallel conductors on
208/230 v units.
5. Circled numerals in Top View refer to condenser fans by position.
6. If spring isolators are used, a perimeter support channel between the unit
and the isolators is recommended.
7. See Table 1 for rigging center of gravity (Dimensions X,Y). See Table 2A
and 2B for A-D corner weights.

Fig. 4 — Dimensions — Unit 38AH104
7

Chart 1, Field Power Supply Connections
UNIT
38AH

VOLTAGE

Hz

QUANTITY

60

DIAMETER
(in.)
35⁄8 (92)

124A
124B

208/230
460, 575,
380
346, 380/415

60

21⁄2 (63)

1

50

35⁄8 (92)

1

LEGEND
C
— Copper Fin Coils
MTG — Mounting
SAE — Society of Automotive Engineers

1

NOTES:
1. The approximate operating weight of the unit is:
38AH-124--7260 lb (3293 kg)
38AH-124--C
8126 lb (3686 kg)
2. Unit must have clearances for airflow as follows:
Top — Do not restrict in any way.
Ends — 5 ft [1524 mm]
Sides — 6 ft [1829 mm]
3. Mounting holes may be used to mount unit to concrete pad. They are not recommended for mounting unit to spring isolators.
4. One 35⁄89 (92-mm) dia hole is recommended for single-entry power into each
module (124A and 124B) of the 208/230-v units.
5. Circled numerals in Top View refer to condenser fans by position.
6. If spring isolators are used, a perimeter support channel between the unit and
the isolators is recommended. Do not support each module separately.
7. Each module of the unit must be rigged into position separately. The unit must
not be rigged after modules have been connected.
8. Suction and liquid connections can exit on either side of the unit.
9. Field power supply connections are required for each module.
10. See Table 1 for rigging center of gravity (Dimensions K,L,X,Y). See Table 2A
and 2B for A-D corner weights.

Fig. 5 — Dimensions — Unit 38AH124
8

Chart 1, Field Power Supply Connections
UNIT
38AH
134A

134B

VOLTAGE

Hz

208/230
460, 575, 380
346, 380/415
208/230
460, 575
380
346, 380/415

60
60
50
60
60
60
50

DIAMETER —
in. (mm)
35⁄8 (92)
21⁄2 (63)
35⁄8 (92)
21⁄2 (63)
21⁄2 (63)
35⁄8 (92)
35⁄8 (92)

LEGEND
C
— Copper Fin Coils
MTG — Mounting
SAE — Society of Automotive Engineers

QUANTITY
1
1
1
2
1
1
1

NOTES:
1. The approximate operating weight of the unit is:
38AH-134--7507 lb (3405 kg)
38AH-134--C
8357 lb (3791 kg)
2. Unit must have clearances for airflow as follows:
Top — Do not restrict in any way.
Ends — 5 ft [1524 mm]
Sides — 6 ft [1829 mm]
3. Mounting holes may be used to mount unit to concrete pad. They are not
recommended for mounting unit to spring isolators.
4. One 35⁄89 (92-mm) dia hole is recommended for single-entry power into
Module 134A and 208/230-v units. Single entry power into Module 134B is
not recommended.
5. Circled numerals in Top View refer to condenser fans by position.
6. If spring isolators are used, a perimeter support channel between the assembled unit and the isolators is recommended. Do not support each module separately.
7. Each module of the unit must be rigged into position separately. The unit
must not be rigged after modules have been connected.
8. Suction and liquid connections can exit on either side of the unit.
9. Field power supply connections are required for each module.
10. See Table 1A or 1B for rigging center of gravity (Dimensions K,L,X,Y). See
Table 2A and 2B for A-D corner weights.

Fig. 6 — Dimensions — Unit 38AH134
9

Table 3A — Units 38AH044-084 Physical Data — 50/60 Hz (English)
38AH
OPERATING WEIGHT WITH
Cu-Al
REFRIGERANT (Approx) — Lb
Cu-Cu
SHIP WEIGHT WITH COIL PROTECTION ONLY
(Approx) — Lb
Cu-Al
Cu-Cu
TYPICAL OPERATING REFRIGERANT
Charge (Approx) — Lb
Qty of Circuits
Std
Opt
COMPRESSOR Type...Rpm
(Qty Cylinder) Compressor*
Std
Model No. 06E
Std
(Qty Cylinder) Compressor*
Opt
Model No. 06E
Opt
Oil Charge (Pt)
Std
Opt
Capacity Control Steps†
CONDENSER FANS (6 Blade) — 60 Hz
Qty...Dia (in.)
Airflow (Cfm)
Speed (Rpm)
Total Power (kW)
CONDENSER FANS (6 Blade) — 50 Hz
Qty...Dia (in.)
Airflow (Cfm)
Speed (Rpm)
Total Power (kW)
CONDENSER COIL
Rows...Fins per in.
Face Area (sq ft)
Storage Capacity (Lb per Circuit) at 120 F
CONNECTIONS
Suction, ODF (in.)**
Liquid, ODF (in.)**
Hot Gas Bypass, ODF (in.)

044
3259
3547

054
3309
3597

3250
3538

3290
3578

064
3565
3998

3530
3963
R-22
62
72
88
2
2
2
1
1
1
Reciprocating Semi-Hermetic...1750 @ 60
(4) A1
(4) B1
(4) A1
(6) B1
(6) A1
(6) B1
250
250
250
265
265
275
(4) A1
(4) A2
(6) A1
(4) A2
(6) A1
(6) A2
250
250
265
250
275
265
17
17
17
21
21
21
17
17
21
17
21
21
4

074
3812
4229

084
4057
4735

3780
4197

4000
4678

104
130
2
2
1
1
Hz; 1458 @ 50 Hz
(6) A1
(6) B1
(6) A1
(6) B1
275
299
299
299
(6) A1
(6) A2
(6) A1
(6) A2
299
275
299
299
21
19
19
19
19
21
19
19

4...30
35,000
1140
6.2

6...30
52,000

4...30
35,000
52,000
950
6.2
Enhanced Copper Tubes, Aluminum Lanced Fin
2...17
3...17
2...19
80.5
80.5
116.7
35
55
55

2...17
80.5
35

51,000
1140
9.3
6...30
51,000
950
9.3
3...17
116.7
80

21⁄8
7⁄8
5⁄8

Table 3B — Units 38AH044-084 Physical Data — 50/60 Hz (SI)
38AH
OPERATING WEIGHT WITH
Cu-Al
REFRIGERANT (Approx) — Kg
Cu-Cu
SHIP WEIGHT WITH COIL PROTECTION ONLY
(Approx) — Kg
Cu-Al
Cu-Cu
TYPICAL OPERATING REFRIGERANT
CHARGE (Approx) — Kg
Qty of Circuits
Std
Opt
COMPRESSOR Type...R/s
(Qty Cylinder) Compressor*
Std
Model No. 06E
Std
(Qty) Cylinder) Compressor*
Opt
Model No. 06E
Opt
Oil Charge (L)
Std
Opt
Capacity Control Steps†
CONDENSER FANS (6 Blade) — 50 Hz
Qty...Dia (mm)
Airflow (L/s)
Speed (R/s)
Total Power (kW)
CONDENSER FANS (6 Blade) — 60 Hz
Qty...Dia (mm)
Airflow (L/s)
Speed (R/s)
Total Power (kW)
CONDENSER COIL
Rows...Fins per m
Face Area (sq m)
Storage Capacity (Kg per Circuit) at 48.9 C
CONNECTIONS
Suction, ODF (in.)**
Liquid, ODF (in.)**
Hot Gas Bypass, ODF (in.)
Cu-Al
Cu-Cu
ODF
Opt
Std

—
—
—
—
—

044
1478
1609

054
1501
1632

1474
1605

1492
1623

28.1
2
1
(4) A1
250
(4) A1
250
8.0
8.0

(4) B1
250
(4) A2
250
8.0
8.0

064
1617
1813

1601
1798
R-22
32.7
39.9
2
2
1
1
Reciprocating Semi-Hermetic...29.2 @ 60
(4) A1
(6) B1
(6) A1
(6) B1
250
265
265
275
(6) A1
(4) A2
(6) A1
(6) A2
265
250
275
265
8.0
9.9
9.9
9.9
9.9
8.0
9.9
9.9
4
4...762
16,500
15.8
6.2

074
1729
1918

084
1840
2148

1715
1904

1814
2122

47.2
2
1
Hz; 24.3 @ 50 Hz
(6) A1
(6) B1
275
299
(6) A1
(6) A2
299
275
9.9
9.0
9.0
9.9

58.9
2
1
(6) B1
299
(6) A2
299
9.0
9.0

6...762
24,500

24,100
15.8
9.3

4...762
16,500
24,500
19.0
6.2
Enhanced Copper Tubes, Aluminum Lanced Fin
2...669
3...669
2...782
7.48
7.48
10.84
16
25
25

2...669
7.48
16

(6) A1
299
(6) A1
299
9.0
9.0

6...762
24,100
19.0
9.3
3...669
10.84
36

21⁄8
7⁄8
5⁄8
**For single-circuit units, suction ODF is 25⁄8 in. (66.7 mm) and liquid ODF is
11⁄8 in. (28.6 mm). Single circuits have a factory-installed manifold; no
field modification is required.

LEGEND
Copper tubes with aluminum fins
Copper tubes with copper fins
Outside Diameter, Female
Optional Single-Circuit Units
Standard Dual-Circuit Units

NOTES:
1. Certified dimensional drawings available on request.
2. Equivalent connection values in mm are as follows:
in.
mm

*Compressor A1 is lead on standard and optional single-circuit units.
†Capacity control steps listed are for constant-volume units with no accessories. Refer to Table 19A or 19B, page 48, for additional system capacity
information.

⁄
⁄
21⁄8
58
78

10

15.9
22.2
54.0

Table 4A — Units 38AH094-134 Physical Data — 50/60 Hz (English)
38AH
OPERATING WEIGHT WITH
REFRIGERANT (Approx) — Lb
SHIP WEIGHT WITH
COIL PROTECTION AND SKID
(Approx) — Lb
TYPICAL OPERATING
REFRIGERANT CHARGE
(Approx) — Lb
Qty of Circuits
COMPRESSOR Type...Rpm
(Qty Cylinder) Compressor†
Model No. 06E
Oil Charge (Pt)
Capacity Control Steps**
CONDENSER FANS (6 Blade) —
Qty...Dia (in.)
Airflow (Cfm)
Speed (Rpm)
Total Power (kW)
CONDENSER FANS (6 Blade) —
Qty...Dia (in.)
Airflow (Cfm)
Speed (Rpm)
Total Power (kW)
CONDENSER COIL
Rows...Fins per in.
Face Area (sq ft)
Storage Capacity
(Lb per circuit) at 120 F
CONNECTIONS
Suction, ODF (in.)
Liquid, ODF (in.)
Hot Gas Bypass, ODF (in.)

Cu-Al
Cu-Cu
Cu-Al
Cu-Cu

094

104

5088
5813
5630
6355

5435
6160
5990
6715

148
2
(6)A1
−275
21

(4)A2
−250
17
5

(6)B1
−299
19

124
124A
3630*
4063*
3907*
4340*

134
124B
3630*
4063*
3907*
4340*

134A
3630*
4063*
3907*
4340*

134B
3877*
4294*
4080*
4497*

R-22
135
88
88
88
2
1
1
1
Reciprocating Semi-Hermetic...1750 @ 60 Hz; 1460 @ 50 Hz
(6)A1 (4)A2 (6)B1 (6)B2 (6)A1 (6)A2 (6)A1 (6)A2 (6)A1 (6)A2
−265 −250 −265 −265 −275 −265 −275 −265 −275 −265
21
17
21
21
21
21
21
21
21
21
6
3
3
3

104
1
(6)A1
−299
19

(6)A2
−275
21
3

60 Hz
6...30
52,000
1140
9.4

6...30
52,000
1140
9.5

4...30
35,000
1140
6.4

4...30
35,000
1140
6.4

4...30
35,000
1140
6.4

6...30
52,000
1140
9.2

6...30
52,000
950
9.4

6...30
4...30
4...30
52,000
35,000
35,000
950
950
950
9.5
6.4
6.4
Enhanced Copper Tubes, Aluminum Lanced Fin
3...17
3...17
3...17
128.3
80.5
80.5
178
110
110

4...30
35,000
950
6.4

6...30
52,000
950
9.2

3...17
80.5
110

2...19
116.7
110

25⁄8
11⁄8
5⁄8

25⁄8
11⁄8
5⁄8

50 Hz

3...17
128.3
178
21⁄8
7⁄8
5⁄8

21⁄8
7⁄8
5⁄8

25⁄8
11⁄8
5⁄8

25⁄8
11⁄8
5⁄8

Table 4B — Units 38AH094-134 Physical Data — 50/60 Hz (SI)
38AH
OPERATING WEIGHT WITH
REFRIGERANT (Approx) — Kg
SHIP WEIGHT WITH
COIL PROTECTION AND SKID
(Approx) — Kg
TYPICAL OPERATING
REFRIGERANT CHARGE
(Approx) — Kg
Qty of Circuits
COMPRESSOR Type...R/s
(Qty Cyliner) Compressor†
Model No. 06E
Oil Charge (L)
Capacity Control Steps**
CONDENSER FANS (6 Blade) —
Qty...Dia (mm)
Airflow (L/s)
Speed (R/s)
Total Power (kW)
CONDENSER FANS (6 Blade) —
Qty...Dia (mm)
Airflow (L/s)
Speed (R/s)
Total Power (kW)
CONDENSER COIL
Rows...Fins per m
Face Area (sq m)
Storage Capacity
(Kg per circuit) at 49 C
CONNECTIONS
Suction, ODF (in.)
Liquid, ODF (in.)
Hot Gas Bypass, ODF (in.)

Cu-Al
Cu-Cu
Cu-Al
Cu-Cu

094

104

2308
2637
2554
2883

2465
2794
2717
3046

67.1
2
(6)A1
−275
10

(4)A2
−250
8
5

(6)B1
−299
9

124
124A
1647*
1843*
1860*
1968*

134
124B
1647*
1843*
1860*
1968*

134A
1647*
1843*
1860*
1968*

R-22
61.2
39.9
39.9
39.9
2
1
1
1
Reciprocating Semi-Hermetic...29.2 @ 60 Hz; 24.3 @ 50 Hz
(6)A1 (4)A2 (6)B1 (6)B2 (6)A1 (6)A2 (6)A1 (6)A2 (6)A1 (6)A2
−265 −250 −265 −265 −275 −265 −275 −265 −275 −265
10
8
10
10
10
10
10
10
10
10
6
3
3
3

134B
1759*
1948*
1851*
1968*

47.2
1
(6)A1
−299
9

(6)A2
−275
10
3

60 Hz
6...762
24,544
19
9.4

6...762
24,544
19
9.5

4...762
16,520
19
6.4

4...762
16,520
19
6.4

4...762
16,520
19
6.4

6...762
24,544
19
9.2

4...762
16,520
15.8
6.4

6...762
24,544
15.8
9.2

3...669.3
7.5
50

2...781.6
10.8
50

25⁄8
11⁄8
5⁄8

25⁄8
11⁄8
5⁄8

50 Hz
6...762
24,544
15.8
9.4
3...669.3
11.9
81
21⁄8
7⁄8
5⁄8

6...762
4...762
4...762
24,544
16,520
16,520
15.8
15.8
15.8
9.5
6.4
6.4
Enhanced Copper Tubes, Aluminum Lanced Fin
3...669.3
3...669.3
3...669.3
11.9
7.5
7.5
81
50
50
21⁄8
7⁄8
5⁄8

LEGEND
Cu-Al — Copper Tubes with Aluminum Fins
Cu-Cu — Copper Tubes with Copper Fins
ODF
— Outside Diameter, Female
*Includes piping and trim kit.
†Compressors are shipped with minimum oil charge.
**Capacity control steps listed are for constant volume units with no accessories. Refer to Table 20, page 48, for additional system capacity information.

25⁄8
11⁄8
5⁄8

25⁄8
11⁄8
5⁄8

NOTES:
1. Unit 38AH124 consists of one 124A module and one 124B module. Unit
38AH134 consists of one 134A module and one 134B module.
2. Certified dimensional drawings available on request.
3. Equivalent connection values in mm are as follows:
in.
mm
⁄
7⁄8
11⁄8
21⁄8
25⁄8
58

11

15.9
22.2
28.6
54.0
66.7

Fig. 7 — Modules 38AH124A or 134A — Shipping Locations of Piping
and Sheet Metal Trim Kit

CONTROL
BOX
SHEET METAL COVER
PANEL (REMOVED)

RIG
HERE

RIG
HERE

RIG
HERE

24-in. (610-mm)
SERVICE SPACE

RIG
HERE

Fig. 8 — Correct Placement of Modules Without Piping
and Sheet Metal Trim (Unit 38AH134 Shown)

12

Fig. 9B — Field-Installed Suction Line Loop

FACTORYINSTALLED
SUCTION
LINE LOOP

Fig. 9A — Typical Module with Cover
Panels Removed
38AH044-084,124,134

MOUNTING SPRINGS

SHIPMENT BOLTS

SHIPMENT BOLTS

38AH094,104

MOUNTING
BOLTS

RAIL BOLT (3) (2 SHOWN)

MOUNTING
BOLTS

RAIL BOLT (3) (2 SHOWN)

Fig. 10 — Outer View, Compressor Mounting
13

38AH044-084 optional single-circuit units) shows required
location of solenoid valves and recommended locations for
the filter driers and sight glasses. Complete the refrigerant
piping from the evaporator to the condenser before opening
the liquid and suction lines at the condenser.

Step 3 — Make Refrigerant Piping
Connections
The field-supplied liquid line solenoid valve must be
installed at the evaporator to avoid possible compressor
damage during unit operation. See Fig. 11 (for 38AH044084 dual-circuit and 38AH094-134 units), or Fig. 12 (for
38AH044-084 optional single-circuit units).

Table 5 — Liquid Lift
UNIT
38AH
044
054
064
074
084
094
104
124
134

The units have large suction lines to minimize friction losses.
The units also have the ability to operate at low capacity.
Because of these capabilities, use special care with suction
piping and suction risers to ensure proper compressor oil
return under all operating conditions. Maximum allowable
vertical separation between the condensing unit and the evaporator is shown in Table 5. Size suction lines in accordance
with Tables 6A or 6B through 9A or 9B and Fig. 13. Mount
liquid line solenoid valve just ahead of the TXVs (thermostatic expansion valves) which will be mounted at the
evaporator. See Fig. 11 (for 38AH044-084 dual-circuit and
38AH094-134 units) or Fig. 12 (for 38AH044-084 optional
single-circuit units).
To achieve good mixing of the refrigerant leaving the evaporator suction header for proper sensing by the TXV bulb:
1. Install a minimum of two 90-degree elbows upstream of
the TXV bulb location. See Fig. 14 (for 38AH044-084
dual-circuit and 38AH094-134 units) or Fig. 15 (for
38AH044-084 optional single-circuit units).
2. Locate the TXV bulb on a vertical riser, where possible.
If a horizontal location is necessary, secure the bulb at
approximately the 4 o’clock position.
3. Size the suction line from the evaporator to the common
suction line to achieve high refrigerant velocity. See
Tables 6A or 6B through 9A or 9B and Fig. 13.
If an oil return connection at the bottom of the suction
header is supplied with an evaporator, tee-in this connection
ahead of first mixing elbow. See Fig. 14 (for 38AH044-084
dual-circuit and 38AH094-134 units) or Fig. 15 (for 38AH044084 optional single-circuit units). When the compressor is
below the evaporator, the riser at the evaporator should extend to the top of the evaporator section. After the riser is
installed, the suction line can elbow down immediately.
Install a field-supplied filter drier and sight glasses in each
refrigerant system. Select the filter drier for maximum unit
capacity and minimum pressure drop. Figure 11 (for 38AH044084 dual-circuit and 38AH094-134 units) or Fig. 12 (for

Ft
69
75
75
45
75
55
50
75
45

MAXIMUM LIQUID LIFT
60 Hz
50 Hz
M
Ft
M
21.0
57.5
17.5
23.0
75.0
23.0
23.0
65.0
19.8
13.7
37.5
11.4
23.0
75.0
23.0
16.7
46.0
14.0
15.2
42.0
12.8
23.0
65.0
19.8
13.7
37.5
11.4

UNITS 38AH044-084 — Relieve the pressure caused by the
holding charge into a refrigerant recovery system. Uncap
the suction line and cut the run-around tube at the liquid line
as close to the loop elbow as possible. This will leave
approximately 2 in. (50 mm) of straight tube for liquid line
connection.
IMPORTANT: Protect the liquid valves from the heat
of brazing.
Leak test the entire system by using soap bubbles and
nitrogen or R-22 with an electronic leak detector.
Purge nitrogen or reclaim R-22 from system after completion of leak-checking procedure. Repair leak if one is
found. When finished, evacuate and dehydrate system using
the methods described in Carrier GTAC II (General Training
Air Conditioning II), Module 4, System Dehydration.
UNITS 38AH094-134 — Relieve the R-22 holding charge
of each circuit into a refrigerant recovery system. Remove
the liquid line to factory-installed suction line loop by cutting the loop at the liquid valve. (See Fig. 9A and 9B.) Cut
as close to the 90-degree bend in the loop as possible. The
remaining tube piece in the valve will be used for brazing
the liquid line. Unbraze and remove the cap from the liquid
line. For 38AH094 and 104 units, sweat-connect the liquid
and suction lines from the evaporator. For 38AH124 and 134
units, see Piping Kit Connections on page 21.

LEGEND
LLS — Liquid Line Solenoid
TXV — Thermostatic Expansion Valve
*Field-Supplied.

Fig. 11 — Required Location of Solenoid Valves and Recommended Filter Drier and
Sight Glass Locations for 38AH044-084 Dual-Circuit and 38AH094-134 Units
14

*Field-Supplied.

Fig. 12 — Required Location of Solenoid Valves and Recommended Filter Drier and
Sight Glass Locations for 38AH044-084 Optional Single-Circuit Units

LEGEND
A
— Pipe A, Suction Riser, without Trap
B
— Pipe B, Suction Riser with Trap
C
— Suction Line to Condensing Unit
D
— Pipe D, Suction Riser Short Lift
RED. — Reducer
STR — Street
NOTES:
1. Short riser, pipe D, is used when routing suction line to condensing unit connection. See table at right.
2. See Tables 6A-9B for values of A, B, and C.

UNIT
38AH
044
054
064
074
084
094, 104
124, 134

PIPE D DIAMETER
Dual Circuit*
Single Circuit*
A
B
in.
mm
in.
mm
in.
mm
41
15⁄8
41
21⁄8
54
15⁄8
15⁄8
41
15⁄8
41
21⁄8
54
15⁄8
41
21⁄8
54
21⁄8
54
21⁄8
54
21⁄8
54
21⁄8
54
21⁄8
54
21⁄8
54
25⁄8†
67†
21⁄8
54
21⁄8
54
—
—
25⁄8
67
25⁄8
67
—
—

*Maximum length of riser is 3 ft (914 mm).
†Double suction riser required if accessory unloader is field
installed.

Fig. 13 — Double Suction Riser Construction
15

Table 6A — Refrigerant Piping Requirements — 38AH044-104 Dual-Circuit Units — 60 Hz
UNIT
38AH
044
054
064
074
084
094
104

Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B

15-25
(4.6-7.6)
L
S
5⁄8
15⁄8
5⁄8
15⁄8
5⁄8
15⁄8
7⁄8
15⁄8
7⁄8
15⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8

TOTAL LINEAR LENGTH OF INTERCONNECTING PIPE — FT (M)
25-50
50-75
75-100
100-150
(7.6-15.2)
(15.2-22.9)
(22.9-30.5)
(30.5-45.7)
L
S
L
S
L
S
L
S
7⁄8
7 ⁄8
7⁄8
7⁄8
15⁄8
21⁄8
21⁄8
21⁄8
7⁄8
7 ⁄8
7⁄8
7⁄8
15⁄8
21⁄8
21⁄8
21⁄8
7⁄8
7 ⁄8
7⁄8
7⁄8
15⁄8
21⁄8
21⁄8
21⁄8
7⁄8
7 ⁄8
21⁄8
21⁄8
11⁄8
21⁄8
11⁄8
21⁄8
7⁄8
7 ⁄8
7⁄8
21⁄8
21⁄8
21⁄8
11⁄8
21⁄8
7⁄8
7 ⁄8
21⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8
7⁄8
7 ⁄8
21⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8†
11⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8
13⁄8
25⁄8
11⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8†
13⁄8
25⁄8†
11⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8
13⁄8
25⁄8
11⁄8
21⁄8
11⁄8
25⁄8†
11⁄8
25⁄8†
13⁄8
25⁄8†
7⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8
11⁄8
25⁄8
11⁄8
21⁄8
11⁄8
25⁄8†
11⁄8
25⁄8†
13⁄8
25⁄8†
11⁄8
21⁄8
11⁄8
25⁄8
11⁄8
25⁄8
13⁄8
31⁄8**

LEGEND

150-200
(45.7-61.0)
L
S
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
11⁄8
25⁄8*
11⁄8
25⁄8†
11⁄8
25⁄8
11⁄8
25⁄8†
13⁄8
25⁄8
13⁄8
25⁄8†
13⁄8
25⁄8
13⁄8
31⁄8**
13⁄8
25⁄8
13⁄8
31⁄8**
13⁄8
31⁄8**

5. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher pressure drop
design criteria may allow selection of smaller pipe sizes, but at a
penalty of decreased system capacity and efficiency.
6. Double suction risers may be required if condensing unit is
elevated above the evaporator. See footnotes and double suction
riser table below.
7. Refer to Carrier System Design Manual or to E20-II design
programs for further information on selecting pipe sizes for split
systems.
8. All pipe sizes are OD inches. Equivalent sizes in millimeters
follow:

L — Liquid Line
S — Suction Line
*Double suction riser required on units with field installed unloader
on circuit B compressor if condensing unit is elevated above
evaporator.
†Double suction riser required on units with field installed unloader
on circuit B compressor if condensing unit is elevated above
evaporator.
**Double suction riser required on all unit configurations if condensing unit is elevated above evaporator.
NOTES:
1. Addition of 2 unloaders to circuit B compressor is not
recommended.
2. 38AH094 and 38AH104 piping sizes apply only to factory supplied unit configurations. They do NOT take into account any field
installed unloaders.
3. Piping sizes are based on unit operation above 40 F (4.4 C) saturated suction temperature (SST). When operating below 40 F
(4.4 C), refer to Carrier System Design Manual, E20-IIT piping design program, or ASHRAE Handbook to select proper line sizes.
4. Pipe sizes are based on the total linear length shown for each
column, plus a 50% allowance for fittings.

in.
5⁄8
7⁄8
11⁄8
13⁄8
15⁄8
21⁄8
25⁄8
31⁄8

mm
15.9
22.2
28.6
34.9
41.3
54.0
66.7
79.4

Table 6B — Refrigerant Piping Requirements for Double Suction Risers,
38AH054-104 Dual-Circuit Units — 60 Hz
UNIT
38AH
054
064
074
084
094
104

Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B

A
—
—
—
—
—
—
—
—
15⁄8
—
13⁄8
—

50-75
(15.2-22.9)
B
—
—
—
—
—
—
—
—
21⁄8
—
21⁄8
—

TOTAL LINEAR LENGTH
75-100
(22.9-30.5)
C
A
B
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
15⁄8
21⁄8
—
—
—
25⁄8
15⁄8
21⁄8
—
—
—
25⁄8
13⁄8
21⁄8
—
—
—

LEGEND

OF INTERCONNECTING PIPE — FT (M)
100-150
(30.5-45.7)
C
A
B
C
A
—
—
—
—
—
—
—
—
—
15⁄8
—
—
—
—
15⁄8
—
—
—
—
—
—
15⁄8
21⁄8
25⁄8
15⁄8
—
—
—
—
—
25⁄8
15⁄8
21⁄8
25⁄8
15⁄8
—
—
—
—
—
25⁄8
15⁄8
21⁄8
25⁄8
15⁄8
—
—
—
—
—
25⁄8
13⁄8
21⁄8
25⁄8
15⁄8
—
13⁄8
25⁄8
31⁄8
15⁄8

150-200
(45.7-61.0)
B
—
21⁄8
21⁄8
—
21⁄8
—
21⁄8
—
25⁄8
—
25⁄8
25⁄8

C
—
25⁄8
25⁄8
—
25⁄8
—
25⁄8
—
31⁄8
—
31⁄8
31⁄8

3. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher design pressure
drop criteria may allow selection of smaller pipe sizes but at a penalty of decreased system capacity and efficiency.
4. Refer to Carrier System Design Manual or to E20-II design
programs for further information on selecting pipe sizes for split
systems.
5. All pipe sizes are OD inches. See Table 6A notes for metric
equivalents.
6. Refer to Fig. 13 for double suction riser construction.

—
— Not Required
Pipe A — Suction Riser Without Trap
Pipe B — Suction Riser With Trap
Pipe C — Suction Line to Condensing Unit
NOTES:
1. See Refrigerant Piping Requirements table at top of page to
determine need for double suction risers.
2. Pipe sizes are based on the total linear length, shown for each
column, plus a 50% allowance for fittings.

16

Table 7A — Refrigerant Piping Requirements, 38AH044-104 Dual-Circuit Units — 50 Hz
UNIT
38AH
044
054
064
074
084
094
104

Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B

15-25
(4.6-7.6)
L
S
5⁄8
13⁄8
5⁄8
13⁄8
5⁄8
13⁄8
7⁄8
15⁄8
7⁄8
15⁄8
7⁄8
15⁄8
7⁄8
15⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8
7⁄8
21⁄8

TOTAL LINEAR LENGTH OF INTERCONNECTING PIPE — FT (M)
25-50
50-75
75-100
100-150
(7.6-15.2)
(15.2-22.9)
(22.9-30.5)
(30.5-45.7)
L
S
L
S
L
S
L
S
7 ⁄8
7 ⁄8
7 ⁄8
7 ⁄8
15⁄8
15⁄8
21⁄8
21⁄8
7 ⁄8
7 ⁄8
7 ⁄8
7 ⁄8
15⁄8
15⁄8
21⁄8
21⁄8
7 ⁄8
7 ⁄8
7 ⁄8
7 ⁄8
15⁄8
15⁄8
21⁄8
21⁄8
7 ⁄8
7 ⁄8
7 ⁄8
15⁄8
21⁄8
21⁄8
11⁄8
21⁄8
7⁄8
7 ⁄8
7 ⁄8
15⁄8
21⁄8†
21⁄8†
11⁄8
21⁄8†
7 ⁄8
7 ⁄8
7 ⁄8
21⁄8
21⁄8
21⁄8
11⁄8
25⁄8*
7 ⁄8
7 ⁄8
7 ⁄8
21⁄8
21⁄8
21⁄8
11⁄8
25⁄8†
7 ⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8
11⁄8
25⁄8
1
1
1
1
5
1
7 ⁄8
2 ⁄8
1 ⁄8
2 ⁄8
1 ⁄8
2 ⁄8†
1 ⁄8
25⁄8†
7 ⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8
11⁄8
25⁄8
11⁄8
21⁄8
11⁄8
25⁄8**
11⁄8
25⁄8**
11⁄8
25⁄8**
7 ⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8*†
11⁄8
25⁄8*†
7 ⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8**
11⁄8
25⁄8**
11⁄8
21⁄8
11⁄8
25⁄8
11⁄8
25⁄8
13⁄8
25⁄8

LEGEND

150-200
(45.7-61.0)
L
S
7 ⁄8
21⁄8
7 ⁄8
21⁄8
7 ⁄8
21⁄8
11⁄8
25⁄8*†
11⁄8
25⁄8**
11⁄8
25⁄8*
11⁄8
25⁄8†
11⁄8
25⁄8
1
1 ⁄8
25⁄8†
11⁄8
25⁄8
13⁄8
31⁄8**
11⁄8
25⁄8*†
13⁄8
31⁄8**
13⁄8
31⁄8**

5. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher pressure drop
design criteria may allow selection of smaller pipe sizes, but at a
penalty of decreased system capacity and efficiency.
6. Double suction risers may be required if condensing unit is
elevated above the evaporator. See footnotes and double suction
riser table below.
7. Refer to Carrier System Design Manual or to E20-II design
programs for further information on selecting pipe sizes for split
systems.
8. All pipe sizes are OD inches. Equivalent sizes in millimeters
follow:

L — Liquid Line
S — Suction Line
*Double suction riser required on units with field installed unloader
on circuit B compressor if condensing unit is elevated above
evaporator.
†Double suction riser required on units with field installed unloader
on circuit B compressor if condensing unit is elevated above
evaporator.
**Double suction riser required on all unit configurations if condensing unit is elevated above evaporator.
NOTES:
1. Addition of 2 unloaders to circuit B compressor is not
recommended.
2. 38AH094 and 38AH104 piping sizes apply only to factory supplied unit configurations. They do NOT take into account any field
installed unloaders.
3. Piping sizes are based on unit operation above 40 F (4.4 C) saturated suction temperature (SST). When operating below 40 F
(4.4 C), refer to Carrier System Design Manual, E20-IIT piping design program, or ASHRAE Handbook to select proper line sizes.
4. Pipe sizes are based on the total linear length shown for each
column, plus a 50% allowance for fittings.

in.
5⁄8
7⁄8
11⁄8
13⁄8
15⁄8
21⁄8
25⁄8
31⁄8

mm
15.9
22.2
28.6
34.9
41.3
54.0
66.7
79.4

Table 7B— Refrigerant Piping Requirements for Double Suction Risers,
38AH054-104 Dual-Circuit Units — 50 Hz
UNIT
38AH
054
064
074
084
094
104

Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B
Ckt A
Ckt B

A
—
—
13⁄8
—
—
—
—
—
13⁄8
—
—
—

50-75
(15.2-22.9)
B
—
—
15⁄8
—
—
—
—
—
21⁄8
—
—
—

TOTAL LINEAR LENGTH
75-100
(22.9-30.5)
C
A
B
—
—
—
—
—
—
21⁄8
13⁄8
15⁄8
—
—
—
—
—
—
—
—
—
—
15⁄8
21⁄8
—
—
—
25⁄8
13⁄8
21⁄8
—
13⁄8
21⁄8
3
—
1 ⁄8
21⁄8
—
—
—

LEGEND

OF INTERCONNECTING PIPE — FT (M)
100-150
(30.5-45.7)
C
A
B
C
A
—
—
—
—
—
—
—
—
—
15⁄8
1
5
5
1
2 ⁄8
1 ⁄8
1 ⁄8
2 ⁄8
15⁄8
—
15⁄8
21⁄8
25⁄8
15⁄8
—
15⁄8
21⁄8
25⁄8
15⁄8
—
—
—
—
—
25⁄8
15⁄8
21⁄8
25⁄8
15⁄8
—
—
—
—
—
25⁄8
15⁄8
21⁄8
25⁄8
15⁄8
25⁄8
15⁄8
21⁄8
25⁄8
15⁄8
5
5
1
5
2 ⁄8
1 ⁄8
2 ⁄8
2 ⁄8
15⁄8
—
—
—
—
15⁄8

150-200
(45.7-61.0)
B
—
21⁄8
21⁄8
21⁄8
21⁄8
—
21⁄8
—
25⁄8
21⁄8
25⁄8
25⁄8

C
—
25⁄8
25⁄8
25⁄8
25⁄8
—
25⁄8
—
31⁄8
25⁄8
31⁄8
31⁄8

3. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher design pressure
drop criteria may allow selection of smaller pipe sizes but at a penalty of decreased system capacity and efficiency.
4. Refer to Carrier System Design Manual or to E20-II design
programs for further information on selecting pipe sizes for split
systems.
5. All pipe sizes are OD inches. See Table 7A notes for metric
equivalents.
6. Refer to Fig. 13 for double suction riser construction.

—
— Not Required
Pipe A — Suction Riser Without Trap
Pipe B — Suction Riser With Trap
Pipe C — Suction Line to Condensing Unit
NOTES:
1. See Refrigerant Piping Requirements table at top of page to
determine need for double suction risers.
2. Pipe sizes are based on the total linear length, shown for each
column, plus a 50% allowance for fittings.

17

Table 8A — Refrigerant Piping Requirements for 38AH044-084
Optional Single-Circuit Units and 38AH124,134
Modular Units (Dual-Circuit) — 60 Hz
UNIT
38AH
044
054
064;
Modules 124A,
124B,134A
074;
Module 134B
084

15-20
(4.6-6.1)
L
S
7⁄8
21⁄8
7⁄8
21⁄8

TOTAL LINEAR
20-50
(6.1-15.2)
L
S
7⁄8
21⁄8
11⁄8
25⁄8

LENGTH OF INTERCONNECTING PIPE — FT (M)
50-75
75-100
100-150
(15.2-22.9)
(22.9-30.5)
(30.5-45.7)
L
S
L
S
L
S
11⁄8
21⁄8
11⁄8
25⁄8*
13⁄8
25⁄8*
11⁄8
25⁄8
11⁄8
25⁄8
13⁄8
31⁄8*

150-200
(45.7-61.0)
L
S
13⁄8
31⁄8*
13⁄8
31⁄8*

11⁄8

21⁄8

11⁄8

25⁄8†

1 1 ⁄8

25⁄8†

13⁄8

31⁄8*

13⁄8

31⁄8*

13⁄8

31⁄8*

11⁄8

21⁄8

11⁄8

25⁄8†

1 3 ⁄8

31⁄8†

13⁄8

31⁄8†

13⁄8

31⁄8†

15⁄8

35⁄8*

11⁄8

25⁄8†

11⁄8

25⁄8†

1 3 ⁄8

31⁄8†

13⁄8

31⁄8†

15⁄8

35⁄8†

15⁄8

35⁄8*

LEGEND
CV — Constant Volume
L
— Liquid Line
S
— Suction Line
VAV — Variable Air Volume
*Double suction riser required on all units configurations if condensing unit is elevated above evaporator.
†Double suction riser required on units with factory installed VAV option or CV units with additional field installed unloader on circuit A1
(lead) compressor if condensing unit is elevated above evaporator.

design criteria may allow selection of smaller pipe sizes, but at a
penalty of decreased system capacity and efficiency.
5. Double suction risers may be required if condensing unit is
elevated above the evaporator. See footnotes and double suction
riser table below.
6. Refer to Carrier System Design Manual, E20-II design program,
or ASHRAE Handbook for further information on selecting pipe
sizes for split systems.
7. All pipe sizes are OD inches. Equivalent sizes in millimeters
follow:
in.
7⁄8
11⁄8
13⁄8
15⁄8
21⁄8
25⁄8
31⁄8
35⁄8

NOTES:
1. Addition of field-installed unloaders on A2 (lag) compressor is not
recommended.
2. Piping sizes are based on unit operation above 40 F (4.4 C) saturated suction temperature (SST). When operating below 40 F
(4.4 C), refer to Carrier System Design Manual, E20-IIT piping
design program, or ASHRAE Handbook to select proper line sizes.
3. Pipe sizes are based on the total linear length shown for each
column, plus a 50% allowance for fittings.
4. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher pressure drop

mm
22.2
28.6
34.9
41.3
54.0
66.7
79.4
92.1

Table 8B — Refrigerant Piping Requirements for Double Suction Risers,
38AH044-084 Optional Single-Circuit Units and 38AH124,134
Modular Units (Dual-Circuit) — 60 Hz

C
—
—

TOTAL LINEAR LENGTH OF INTERCONNECTING PIPE — FT
50-75
75-100
100-150
(15.2-22.9)
(22.9-30.5)
(30.5-45.7)
A
B
C
A
B
C
A
B
C
—
—
—
15⁄8
21⁄8
25⁄8
15⁄8
21⁄8
25⁄8
—
—
—
—
—
—
15⁄8
25⁄8
31⁄8

150-200
(45.7-61.0)
A
B
C
15⁄8
25⁄8
31⁄8
15⁄8
25⁄8
31⁄8

21⁄8

25⁄8

15⁄8

21⁄8

25⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

15⁄8

21⁄8

25⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

21⁄8

31⁄8

35⁄8

15⁄8

21⁄8

25⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

21⁄8

31⁄8

35⁄8

21⁄8

31⁄8

35⁄8

UNIT
38AH
044
054
064
Modules 124A,
124B,134A
074;
Module 134B
084

A
—
—

15-50
(4.6-15.2)
B
—
—

15⁄8

LEGEND

3. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher design pressure
drop criteria may allow selection of smaller pipe sizes but at a penalty of decreased system capacity and efficiency.
4. Refer to Carrier System Design Manual or to E20-II design
programs for further information on selecting pipe sizes for split
systems.
5. All pipe sizes are OD inches. See Table 8A notes for metric
equivalents.
6. Refer to Fig. 13 for double suction riser construction.

—
— Not Required
Pipe A — Suction Riser Without Trap
Pipe B — Suction Riser With Trap
Pipe C — Suction Line to Condensing Unit
NOTES:
1. See Refrigerant Piping Requirements table at top of page to determine need for double suction risers.
2. Pipe sizes are based on the total linear length, shown for each
column, plus a 50% allowance for fittings.

18

Table 9A — Refrigerant Piping Requirements for 38AH044-084
Optional Single-Circuit Units and 38AH124,134
Modular Units (Dual Circuit) — 50 Hz
UNIT
38AH

15-20
(4.6-6.1)
L
S
7⁄8
21⁄8
7⁄8
21⁄8

044
054
064;
Modules 124A,
124B, 134A
074;
Module 134B
084

TOTAL LINEAR LENGTH OF INTERCONNECTING PIPE — FT (M)
20-50
50-75
75-100
100-150
(6.1-15.2)
(15.2-22.9)
(22.9-30.5)
(30.5-45.7)
L
S
L
S
L
S
L
S
7 ⁄8
21⁄8
11⁄8
21⁄8
11⁄8
25⁄8*
11⁄8
25⁄8*
11⁄8
21⁄8
11⁄8
25⁄8*
11⁄8
25⁄8*
11⁄8
25⁄8*

150-200
(45.7-61.0)
L
S
13⁄8
25⁄8*
13⁄8
31⁄8*

78

⁄

21⁄8

11⁄8

25⁄8†

11⁄8

25⁄8†

11⁄8

25⁄8†

13⁄8

31⁄8*

13⁄8

31⁄8*

78

⁄

21⁄8

11⁄8

25⁄8†

11⁄8

25⁄8†

13⁄8

31⁄8*

13⁄8

31⁄8*

13⁄8

31⁄8*

11⁄8

21⁄8

11⁄8

25⁄8†

13⁄8

31⁄8*

13⁄8

31⁄8*

13⁄8

31⁄8*

15⁄8

35⁄8*

LEGEND

design criteria may allow selection of smaller pipe sizes, but at a
penalty of decreased system capacity and efficiency.
5. Double suction risers may be required if condensing unit is
elevated above the evaporator. See footnotes and double suction
riser table below.
6. Refer to Carrier System Design Manual, E20-II design program,
or ASHRAE Handbook for further information on selecting pipe
sizes for split systems.
7. All pipe sizes are OD inches. Equivalent sizes in millimeters
follow:

CV — Constant Volume
L
— Liquid Line
S
— Suction Line
VAV — Variable Air Volume
*Double suction riser required on all units configurations if condensing unit is elevated above evaporator.
†Double suction riser required on units with factory installed VAV option or CV units with additional field installed unloader on circuit A1
(lead) compressor if condensing unit is elevated above evaporator.

in.
7⁄8
11⁄8
13⁄8
15⁄8
21⁄8
25⁄8
31⁄8
35⁄8

NOTES:
1. Addition of field-installed unloaders on A2 (lag) compressor is not
recommended.
2. Piping sizes are based on unit operation above 40 F (4.4 C) saturated suction temperature (SST). When operating below 40 F
(4.4 C), refer to Carrier System Design Manual, E20-IIT piping
design program, or ASHRAE Handbook to select proper line sizes.
3. Pipe sizes are based on the total linear length shown for each
column, plus a 50% allowance for fittings.
4. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher pressure drop

mm
22.2
28.6
34.9
41.3
54.0
66.7
79.4
92.1

Table 9B — Refrigerant Piping Requirements for Double Suction Risers,
38AH044-084 Optional Single-Circuit Units and 38AH124,134
Modular Units (Dual Circuit) — 50 Hz
UNIT
38AH
044
054
064;
Modules 124A,
124B, 134A
074;
Module 134B
084

15-20
(4.6-6.1)
A
B
C
—
—
—
—
—
—

TOTAL LINEAR LENGTH OF INTERCONNECTING PIPE — FT (M)
20-50
50-75
75-100
100-150
(6.1-15.2)
(15.2-22.9)
(22.9-30.5)
(30.5-45.7)
A
B
C
A
B
C
A
B
C
A
B
C
—
—
—
—
—
—
15⁄8
21⁄8
25⁄8
15⁄8
25⁄8
25⁄8
—
—
—
15⁄8
21⁄8
25⁄8
15⁄8
21⁄8
25⁄8
15⁄8
21⁄8
25⁄8

150-200
(45.7-61.0)
A
B
C
15⁄8
25⁄8
25⁄8
15⁄8
25⁄8
31⁄8

—

—

—

15⁄8

21⁄8

25⁄8

15⁄8

21⁄8

25⁄8

15⁄8

21⁄8

25⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

—

—

—

15⁄8

21⁄8

25⁄8

15⁄8

21⁄8

25⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

15⁄8

31⁄8

35⁄8

—

—

—

15⁄8

21⁄8

25⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

15⁄8

25⁄8

31⁄8

15⁄8

31⁄8

35⁄8

LEGEND

3. Suction and liquid line sizing is based on pressure drop equivalent
to 2 F (1.1 C) at nominal rating conditions. Higher design pressure
drop criteria may allow selection of smaller pipe sizes but at a penalty of decreased system capacity and efficiency.
4. Refer to Carrier System Design Manual or to E20-II design
programs for further information on selecting pipe sizes for split
systems.
5. All pipe sizes are OD inches. See Table 9A notes for metric
equivalents.
6. Refer to Fig. 13 for double suction riser construction.

—
— Not Required
Pipe A — Suction Riser Without Trap
Pipe B — Suction Riser With Trap
Pipe C — Suction Line to Condensing Unit
NOTES:
1. See Refrigerant Piping Requirements table at top of page to
determine need for double suction risers.
2. Pipe sizes are based on the total linear length, shown for each
column, plus a 50% allowance for fittings.

19

LEGEND
TXV — Thermostatic Expansion Valve
TYP — Typical
NOTE: Lower split first on, last off.

Fig. 14 — Typical Piping Connections for Face Split Coils for 38AH044-084 Dual-Circuit
and 38AH094-134 Units

LEGEND
TXV — Thermostatic Expansion Valve
TYP — Typical
NOTE: Lower split first on, last off.

Fig. 15 — Typical Piping Connections for Face Split Coils for 38AH044-084
Optional Single-Circuit Units
20

align holes and reinsert screws B. Place horizontal cover on
top of Module 134A end cover with opposite side resting on
the horizontal flange of the installed Module B vertical top
cover piece. Align holes on flange and top cover. Reinsert
screws A through the top cover holes into the end cover. From
within the service space, insert supplied screws up through
the flange and horizontal cover to make a secure connection
between the horizontal and vertical cover pieces.
Insert supplied screws into each of the 2 holes in the vertical side flange of the top cover at each end of the service
space.
Attach Side Panels — Insert side panels at the ends of the
service space and hook side panel flange over the 2 screws
previously inserted in the top cover flange. Fasten panels to
the corner posts with supplied self-drilling screws, 3 per side.
See Fig. 19.
Connect Tubing from Evaporator to Unit

Units 38AH124 and 134 Piping Kit Connections — The
38AH124 and 134 units are delivered with a factorysupplied suction and liquid piping kit for installation in the
24-in. (610-mm) service space between the 2 unit modules.
The piping kit allows for a common unit side piping connection from the indoor unit to each of the condensing unit
refrigeration circuits. Fittings are provided and shipped in
the control box.
Remove the copper tubes from Module 124A or 134A compressor rails. Save the pipe clamps for later use. Cut the
25⁄8-in. (67-mm) suction tube into 2 pieces: 28 in. (711 mm)
and 67 in. (1702 mm). Connect the 2 formed 11⁄8-in.
(29-mm) tubes to the liquid line connection at the liquid valve.
See Fig. 16.
NOTE: Piping kit is designed to allow air handler connections to project from either side of the service space.
To prepare condensing unit modules for piping connection, refer to beginning paragraphs of Step 3 — Make
Refrigeration Piping Connections, page 14.
Two 25⁄8-in. (67-mm) and one 11⁄8-in. (29-mm) elbows are
supplied for piping connections. Fit tubing to ensure proper
installation. All tubes should have equal lengths projecting
beyond unit corner posts. See Fig. 16. Ensure suction tube
is level for oil return requirements.

Protect liquid valves from the heat of brazing.
Braze the liquid and suction lines from the evaporator to
the condensing unit liquid and suction lines. Leak test the
entire system by the pressure method described in the
Carrier Standard Service Techniques Manual, Chapter 1,
Section 1-6. Use R-22 at approximately 25 psig (172 kPa)
backed up with an inert gas to a total pressure not to exceed
245 psig (1689 kPa). If a leak is detected, evacuate and dehydrate the system. Follow methods described in the Carrier
Service Manual, Chapter 1, Section 1-7.

Protect liquid valves from the heat of brazing.
Braze the piping connections.
Level the tubes and clamp to the corner posts with factorysupplied self-drilling screws and pipe clamps removed from
Module 124A or 134A during piping kit removal.
Units 38AH124 and 134 Sheet Metal Trim Kit Installation
— After the units are in place and the piping kit is installed,
install the sheet metal trim kit.
NOTE: Install sheet metal trim kit before connection to air
handler tubing in case the modules must be repositioned to
accommodate the sheet metal installation.
Remove two 43-in. (1092 mm) base rail trim pieces from
Module 124A or 134A base rail. Remove the 3 corner post
bolts from the bottom of each corner post at the service space.
Align the base rail trim piece holes over the bolt holes in the
corner rails. See Fig. 17. Reinsert corner post bolts through
the trim piece into the corner posts.
Attach Top Cover — To attach top cover, proceed as
follows:
For Unit 38AH124, remove screws A from top of each of
4 corner posts at service space. See Fig. 18. Place cover on
top of service space and align top cover slots with corner
post screw holes. Reinsert screws A.
For Unit 38AH134, remove screws A from top of each corner post on Module 134A and screws B from top of each
corner post on Module 134B. See Fig. 18. Top cover is in
2 pieces: one vertical piece and one horizontal piece. Slide
vertical top cover partly under Module 134B end cover flange;

NOTES:
1. Ensure suction tube is level for oil return requirements.
2. Protect liquid valves from heat of brazing.

Fig. 16 — Units 38AH124 and 134 with Installed
Piping Kit

21

MODULE
124B
OR 134B

BASE RAIL
BOLTS (6)

CORNER
POST

CORNER POST

CORNER
SCREWS (2)
POST (4 PER FOR
MODULE)
MOUNTING
SIDE PANEL

FACTORY-SUPPLIED
SELF-DRILLING
SCREWS (4 PER
CORNER POST)

Fig. 17 — Units 38AH124 and 134 with Installed Trim
Kit Rails

CORNER TOP
POST
COVER
(4 PER
FLANGE
MODULE)

MODULE
124A
OR 134A

24-in. (610-mm)
SERVICE WAY

Fig. 19 — Fully Assembled Piping and Trim Kit
(Unit 38AH134 Shown)

SCREWS B
END COVER
FLANGES

CORNER
POST

TOP COVER, SCREWS A
TOP COVER,
HORIZONTAL
VERTICAL
PIECE
PIECE
VERTICAL
TOP COVER
END COVER
FLANGE
(HIDDEN)

MODULE 124B 24-in. (610-mm)
SERVICE WAY
OR 134B

CORNER
POST

MODULE 124A
OR 134A

Fig. 18 — Units 38AH124 and 134 with Installed Top
Cover (Unit 38AH134 Shown)

22

MAIN POWER — Units 38AH044-104 have single-point
power connection to simplify field-power wiring (all power
enters at one end). Units 38AH124 and 134 require 2 connection points, one for each module. Units may use copper,
copper-clad aluminum, or aluminum conductors at all voltages. The maximum wire size units can accept per terminal
block is 500 kcmil.
Power must be supplied as shown in Table 15.

Step 4 — Make Electrical Connections
POWER SUPPLY — Electrical characteristics of available
power supply must agree with unit nameplate rating. Supply
voltage must be within the limits shown in Tables 10A or
10B, 11 and 12. See Table 13 for control circuit data and
Table 14 for fan motor electrical data.
IMPORTANT: Operation of unit on improper supply
voltage or with excessive phase imbalance constitutes
abuse and can affect any Carrier warranty.

CONTROL CIRCUIT WIRING — Control circuit wiring is
accomplished with a step-down transformer on voltage designations 500, 600, and 100 in table below where the primary voltage is field voltage. For 208/230-v, 3-ph, 60-Hz
units, ensure that the transformer primary is wired properly
for the voltage which will be applied. All control wiring must
comply with applicable local and national codes. The safety
circuits are 24 v on all units. The safety circuit voltage is
created with a step-down transformer where main control
voltage is the transformer primary voltage.
See Table 13 for control circuit information.

FIELD POWER CONNECTIONS — All power wiring must
comply with applicable local and national codes. Install fieldsupplied, branch circuit safety disconnect(s) of a type that
can be locked off/open. Disconnects must be located within
sight of, and readily accessible from, the unit in compliance
with NEC (National Electrical Code) (U.S.A. Standard)
Article 440-14.
All field power enters the unit through a hole in the control box shelf. Refer to Fig. 20-28 for field wiring details.

Table 10A — Electrical Data — 50/60 Hz (38AH044-084 Dual-Circuit Units)
STANDARD UNIT
38AH

044

054

064

074

084

Voltage
Designation
500
600
100
200
800 (PW)
900
300 (PW)
500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)

Compressor
A1/B1
Model No.

06E4250/250

06E4250/265

06E8265/275

06E8275/299

06E8299/299

Nameplate
V-Ph-Hz
208/230-3-60
460-3-60
575-3-60
380-3-60
230-3-50
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50

COMPRESSOR*

Supply Voltage†
Min

Max

187
414
518
342
198
342
325
187
414
518
342
342
325
187
414
518
342
342
325
187
414
518
342
342
325
187
414
518
342
342
325

254
508
632
418
254
440
367
254
508
632
418
440
367
254
508
632
418
440
367
254
508
632
418
440
367
254
508
632
418
440
367

See page 24 for Legend and Notes.

23

MCA

MOCP

ICF

179.4
91.3
78.4
93.5
180.2
91.5
100.0
206.6
102.4
88.0
107.1
102.7
107.0
249.3
115.5
100.6
126.9
114.1
129.8
330.5
148.6
132.2
174.5
143.0
170.8
371.5
167.2
148.9
200.7
167.6
205.3

225
100
100
125
225
100
125
250
125
125
150
125
150
350
150
125
175
150
175
450
200
175
250
200
250
500
225
200
250
225
250

434.7
218.6
162.4
241.2
296.7
219.6
165.9
535.7
268.6
206.4
297.2
269.6
198.9
617.5
307.6
226.1
341.1
335.6
230.5
829.0
408.2
336.8
458.0
403.8
300.4
870.0
426.8
353.5
484.2
428.4
334.9

A1

B1

RLA

LRA

RLA

LRA

67.9
34.6
28.8
34.6
67.9
34.6
33.3
67.9
34.6
28.8
34.6
34.6
33.3
89.7
43.6
36.5
45.5
43.6
44.9
106.4
46.8
40.4
52.6
46.8
53.8
147.4
65.4
57.1
78.8
65.4
79.5

345
173
120
191
207
173
115
345
173
120
191
173
115
446
223
164
247
223
148
506
253
176
280
280
168
690
345
276
382
345
229

67.9
34.6
28.8
34.6
67.9
34.6
33.3
89.7
43.6
36.5
45.5
43.6
44.9
106.4
46.8
40.4
52.6
46.8
53.8
147.4
65.4
57.1
78.8
65.4
79.5
147.4
65.4
57.1
78.8
65.4
79.5

345
173
120
191
207
173
115
446
223
164
247
223
148
506
253
176
280
280
168
690
345
276
382
345
229
690
345
276
382
345
229

Table 10B — Electrical Data — 50/60 Hz (38AH044-084 Optional Single-Circuit Units)

38AH

044

054

064

074

084

Voltage
Designation
500
600
100
200
800 (PW)
900
300 (PW)
500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)

OPTIONAL SINGLE-CIRCUIT UNIT
Compressor
Supply Voltage
Nameplate
A1/A2
V-Ph-Hz
Min
Max
Model No.

06E4250/250

06E4265/250

06E8275/265

06E8299/275

06E8299/299

208/230-3-60
460-3-60
575-3-60
380-3-60
230-3-50
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50

187
414
518
342
198
342
325
187
414
518
342
342
325
187
414
518
342
342
325
187
414
518
342
342
325
187
414
518
342
342
325

254
508
632
418
254
440
367
254
508
632
418
440
367
254
508
632
418
440
367
254
508
632
418
440
367
254
508
632
418
440
367

LEGEND
— Full Load Amps
— Maximum Instantaneous Current Flow During Starting.
(The point in the starting sequence where the sum of
the LRA for the starting compressors, plus the total RLA
for all running compressors, plus the FLA for all running
fan motors is maximum.)
kcmil — Thousand Circular Mils
LRA
— Locked Rotor Amps
Max
— Maximum
MCA — Minimum Circuit Amps (used for sizing; complies with
National Electrical Code [NEC] [U.S.A. Standard],
section 430-24).
Min
— Minimum
MOCP — Maximum Overcurrent Protection (used for sizing disconnect; complies with NEC Article 440, Section 22).
RLA
— Rated Load Amps
PW
— Part Wind Only

COMPRESSOR*
MCA

MOCP

ICF

179.4
91.3
78.4
93.5
180.2
91.5
100.0
206.6
102.4
88.0
107.1
102.7
107.0
249.3
115.5
100.6
126.9
115.7
129.8
330.5
148.6
132.2
174.5
143.0
170.8
371.5
167.2
148.9
200.7
167.6
205.3

225
100
100
125
225
100
125
250
125
125
150
125
150
350
150
125
175
150
175
450
200
175
250
200
250
500
225
200
250
225
250

434.7
218.6
162.4
241.2
296.7
219.6
165.9
535.7
268.6
206.4
297.2
269.6
198.9
617.5
307.6
226.1
341.1
335.6
230.5
829.0
408.2
336.8
458.0
403.8
300.4
870.0
426.8
353.5
484.2
428.4
334.9

A1

A2

RLA

LRA

RLA

LRA

67.9
34.6
28.8
34.6
67.9
34.6
33.3
89.7
43.6
36.5
45.5
43.6
44.9
106.4
46.8
40.4
52.6
46.8
53.8
147.4
65.4
57.1
78.8
65.4
79.5
147.4
65.4
57.1
78.8
65.4
79.5

345
173
120
191
207
173
115
446
223
164
247
223
148
506
253
176
280
280
168
690
345
276
382
345
229
690
345
276
382
345
229

67.9
34.6
28.8
34.6
67.9
34.6
33.3
67.9
34.6
28.8
34.6
34.6
33.3
89.7
43.6
36.5
45.5
43.6
44.9
106.4
46.8
40.4
52.6
46.8
53.8
147.4
65.4
57.1
78.8
65.4
79.5

345
173
120
191
207
173
115
345
173
120
191
173
115
446
223
164
247
223
148
506
253
176
280
280
168
690
345
276
382
345
229

*All compressors are across-the-line start only except 38AH044
230 v, 3-phase, 50 Hz; and all 346 v, 3-phase, 50 Hz.
†Units are suitable for use on electrical systems where voltage supplied to unit terminals is within listed minimum to maximum limits.

FLA
ICF

NOTES:
1. Maximum allowable phase imbalance: voltage - 2%; amps - 10%.
2. Maximum incoming wire size for terminal block is 500 kcmil.

24

Table 11 — Electrical Data — 50/60 Hz (Units 38AH094,104)
UNIT
38AH

094

104

VOLTAGE
DESIGNATION

NAMEPLATE
V-Ph-Hz

500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)

208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50

SUPPLY
VOLTAGE*

MCA

MOCP

ICF

Min
187
414
518
342
342
325
187
414
518
342
342
325

398.5
183.1
160.9
209.1
183.6
212.9
399.4
196.3
168.0
205.9
196.7
205.6

500
225
200
250
225
250
450
225
200
250
225
250

897
443
366
493
444
343
722
361
286
396
363
298

Max
253
506
633
418
440
380
253
506
633
418
440
380

LEGEND
— Not Applicable
— Full Load Amps
— Maximum Instantaneous Current Flow During Starting.
(The point in the starting sequence where the sum of
the LRA for the starting compressors, plus the total RLA
for all running compressors, plus the FLA for all running
fan motors is maximum.)
kcmil — Thousand Circular Mils
LRA
— Locked Rotor Amps
MCA — Minimum Circuit Amps (used for sizing; complies with
National Electrical Code [NEC] [U.S.A. Standard],
section 430-24).
MOCP — Maximum Overcurrent Protection (used for sizing
disconnect; complies with NEC [U.S.A. Standard],
section 440-22).
RLA
— Rated Load Amps

A1
RLA LRA
106.4 506
46.8 253
40.4 176
52.6 280
46.8 280
53.8 168
89.7 446
43.6 223
36.5 164
45.5 247
43.6 223
44.9 148

COMPRESSOR†
A2
B1
RLA LRA RLA LRA
67.9
345 147.7 690
34.6
173
65.4
345
28.8
120
57.1
276
34.6
191
78.8
382
34.6
173
65.4
345
33.3
115
79.5
229
67.9
345
89.7
446
34.6
173
43.6
223
28.8
120
36.5
164
34.6
191
45.5
247
34.6
173
43.6
223
33.3
229
44.9
148

B2
RLA LRA
—
—
—
—
—
—
—
—
—
—
—
—
89.7
446
43.6
223
36.5
164
45.5
247
43.6
223
49.9
148

*Units are suitable for use on electrical systems where voltage supplied to unit terminals is within listed minimum to maximum limits.
†All compressors are across-the-line start only except 346-V, 3-ph,
50-Hz units.

—
FLA
ICF

NOTES:
1. Maximum allowable phase imbalance: voltage - 2%; amps - 10%.
2. Maximum incoming wire size for terminal block is 500 kcmil.
3. For units 38AH094 and 104 compressor model numbers, see table
below:
UNIT
38AH
CKT
MODEL
NO. 06E

25

094

104

A1

A2

B1

A1

A2

B1

B2

−275

−250

−299

−265

−250

−265

−265

Table 12 — Electrical Data — 50/60 Hz (Units 38AH124, 134)
UNIT
38AH
MODULE

124A
124B
134A

134B

VOLTAGE
DESIGNATION

COMPRESSOR
A1/A2
MODEL NO.

500
600
100
200
900
300 (PW)
500
600
100
200
900
300 (PW)

06E8275/
265

06E8299/
275

NAMEPLATE
V-Ph-Hz
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50

SUPPLY
VOLTAGE*

MCA

MOCP

ICF

Min
187
414
518
342
342
325
187
414
518
342
342
325

249.3
115.5
100.6
126.9
115.7
129.8
330.5
148.6
132.2
174.5
149.0
170.8

350
150
125
175
150
175
450
200
175
250
200
250

617.5
307.6
226.1
341.1
335.6
230.5
829.0
408.2
336.8
458.0
403.8
300.4

LEGEND

Max
254
508
632
418
440
367
254
508
632
418
440
367

COMPRESSOR†
A1
A2
RLA
LRA
RLA
LRA
106.4
506
89.7
446
46.8
253
43.6
223
40.4
176
36.5
164
52.6
280
45.5
247
46.8
280
43.6
223
53.8
168
44.9
148
147.4
690
106.4
506
65.4
345
46.8
253
57.1
276
40.4
176
78.8
382
52.6
280
65.4
345
46.8
280
79.5
229
53.8
168

*Units are suitable for use on electrical systems where voltage supplied to unit terminals is within listed minimum to maximum limits.
†All compressors are across-the-line start only except 346-v, 3-ph,
50 Hz unit.
NOTES:
1. Maximum allowable phase imbalance: voltage - 2%; amps - 10%.
2. Maximum incoming wire size for terminal block is 500 kcmil.

FLA
ICF

— Full Load Amps
— Maximum Instantaneous Current Flow During Starting.
(The point in the starting sequence where the sum of
the LRA for the starting compressors, plus the total RLA
for all running compressors, plus the FLA for all running
fan motors is maximum.)
kcmil — Thousand Circular Mils
LRA
— Locked Rotor Amps
MCA — Minimum Circuit Amps (used for sizing; complies with
National Electrical Code [NEC] [U.S.A. Standard],
section 430-24).
MOCP — Maximum Overcurrent Protection (used for sizing
disconnect; complies with NEC [U.S.A. Standard],
section 440- 22).
PW
— Part Wind
RLA
— Rated Load Amps

Table 13 — Control Circuit Electrical Data — 50/60 Hz
UNIT
DESIGNATION
−500
−600
−100
−200
−800
−900
−300

UNIT POWER
V-Ph-Hz
208/230-3-60
460-3-60
575-3-60
380-3-60
230-3-50
380/415-3-50
346-3-50

CONTROL POWER
V-Ph-Hz
Min
Max
115-1-60
103
127
115-1-60
103
127
115-1-60
103
127
230-1-60
207
253
230-1-50
207
253
230-1-50
207
253
200-1-50
180
220

NOTE: Units 38AH124 and 134 have 2 control boxes per unit, one in each module.

26

AMPS
4.1
4.1
4.1
2.0
2.0
2.0
2.4

Table 14 — Fan Motor Electrical Data
UNIT
38AH

044

054

064

074

084

094

104

Nameplate
V-Ph-Hz
208/230-3-60
460-3-60
575-3-60
380-3-60
230-3-50
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50

Qty

Hp
(kW)

4

1
(0.746)

4

1
(0.746)

4

1
(0.746)

6

1
(0.746)

6

1
(0.746)

6

1
(0.746)

6

1
(0.746)

CONDENSER FAN
Total
(No.*) FLA Each
kW
(1,2) 5.5 (3,4) 6.6
(1,2) 2.8 (3,4) 3.3
(1-4) 3.4
6.2
(1-4) 3.9
(1,2) 5.5 (3,4) 6.8
(1-4) 3.4
(1-4) 4.4
(1,2) 5.5 (3,4) 6.6
(1,2) 2.8 (3,4) 3.3
(1-4) 3.4
6.2
(1-4) 3.9
(1-4) 3.4
(1-4) 4.4
(1,2) 5.5 (3,4) 6.6
(1,2) 2.8 (3,4) 3.3
(1-4) 3.4
6.2
(1-4) 3.9
(1-4) 3.4
(1-4) 4.4
(1,2) 5.5 (3-6) 6.6
(1,2) 2.8 (3-6) 3.3
(1-6) 3.4
9.3
(1-6) 3.9
(1-6) 3.4
(1-6) 4.4
(1,2) 5.5 (3-6) 6.6
(1,2) 2.8 (3-6) 3.3
(1-6) 3.4
9.3
(1-6) 3.9
(1-6) 3.4
(1-6) 4.4
(1,2) 5.5 (3-6) 6.6
(1-2) 2.8 (3-6) 3.3
(1-6) 3.4
9.4
(1-6) 3.9
(1-6) 3.4
(1-6) 4.4
(1,2) 5.5 (3-6) 6.6
(1,2) 2.8 (3-6) 3.3
(1-6) 3.4
9.5
(1-6) 3.9
(1-6) 3.4
(1-6) 4.4

(No.*) LRA Each
(1,2) 30.0 (3,4) 31.6
(1,2) 30.0 (3,4) 31.6
(1-4) 30.0
(1-4) 20.9
(1,2) 30.0 (3,4) 31.6
(1-4) 30.0
(1-4) 20.9
(1,2) 30.0 (3,4) 31.6
(1,2) 30.0 (3,4) 31.6
(1-4) 30.0
(1-4) 20.9
(1-4) 30.0
(1-4) 20.9
(1,2) 30.0 (3,4) 31.6
(1,2) 30.0 (3,4) 31.6
(1-4) 30.0
(1-4) 20.9
(1-4) 30.0
(1-4) 20.9
(1,2) 30.0 (3-6) 31.6
(1,2) 30.0 (3-6) 31.6
(1-6) 30.0
(1-6) 20.9
(1-6) 30.0
(1-6) 20.9
(1,2) 30.0 (3-6) 31.6
(1,2) 30.0 (3-6) 31.6
(1-6) 30.0
(1-6) 20.9
(1-6) 30.0
(1-6) 20.9
(1,2) 30.0 (3-6) 31.6
(1,2) 30.0 (3-6) 31.6
(1-6) 30.0
(1-6) 20.9
(1-6) 30.0
(1-6) 20.9
(1,2) 30.0 (3-6) 31.6
(1,2) 30.0 (3-6) 31.6
(1-6) 30.0
(1-6) 20.9
(1-6) 30.0
(1-6) 20.9

UNIT 38AH
MODULE

124A
124B
134A

134B

208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50
208/230-3-60
460-3-60
575-3-60
380-3-60
380/415-3-50
346-3-50

4

6

1
(0.746)

6.4

1
(0.746)

9.2

LEGEND

(1,2) 5.5 (3,4)
(1,2) 2.8 (3,4)
(1-4) 3.4
(1-4) 3.9
(1-4) 3.4
(1-4) 4.4
(1,2) 5.5 (3-6)
(1,2) 2.8 (3-6)
(1-6) 3.4
(1-6) 3.9
(1-6) 3.4
(1-6) 4.4

6.6
3.3

6.6
3.3

(1,2) 30.0 (3,4)
(1,2) 30.0 (3,4)
(1-4) 30.0
(1-4) 20.9
(1-4) 30.0
(1-4) 20.9
(1,2) 30.0 (3-6)
(1,2) 30.0 (3-6)
(1-6) 30.0
(1-6) 20.9
(1-6) 30.0
(1-6) 20.9

31.6
31.6

31.6
31.6

*Refers to condenser fans by position: See circled numbers on top
views of units in Fig. 1-6.
NOTE: All fans are protected by a single circuit breaker.

FLA — Full Load Amps
LRA — Locked Rotor Amps

27

Internal 33CSUCE-06 relay contacts are rated for 1 amp/24 vac.

*To control heating device and provide automatic indoorfan operation on heating.
†Jumper removed only when separate 24-v transformer power source is used to power the 33CSUCE-06
relay pack.
**Field-supplied.

NOTES:
1. Liquid line solenoid valve LLS-A is used for solenoid drop on circuit A. Liquid line solenoid valve
LLS-B is used for solenoid drop for circuit B.
2. Solenoid drop is a safety feature which prevents refrigerant migration to the compressor during the OFF cycle. It is recommended on all
systems and required on systems where piping
exceeds 75 ft (22.9 m) in length.
3. The 33CSUCE-06 relay pack requires 10 va.
4. Factory wiring is in accordance with NEC; field
modifications or additions must be in compliance with all applicable codes.
5. Wiring for field power supply must be rated
75 C minimum. Use copper, copper-clad aluminum, or aluminum conductors. Maximum incoming wire size for each terminal block is
500 kcmil.
6. Terminal blocks TB3 and TB4 are for external
field control connections. Control connections
are to be Class 1 wiring.
7. Field-supplied components (IFC, LLS-A, and
LLS-B) must have a maximum sealed coil rating of 30 va each (0.25 amp at 120 vac and

8.
9.
10.
11.

0.13 amp at 230 vac). Thermostats must have a
minimum pilot duty rating of 300 va (2.5 amps at
120 vac and 1.3 amps at 230 vac).
Replacement of factory wires must be with type
105 C wire or its equivalent.
Field-supplied liquid line solenoid valves installed
at the evaporator are required on all units.
Units have 175 va of power available for fieldinstalled accessories.
To minimize voltage drop, the following wire sizes
are recommended:
LENGTH —
Ft (M)
Up to 50
(15.2)
50-75
(15.2-22.9)
More Than 75
(22.9)

INSULATED WIRE — AWG
(35 C Minimum)
No. 18

AWG
CR
HD
IFC
IFR
kcmil
LLS
NEC
R
RV
TB

LEGEND
American Wire Gage
Control Relay
Heating Device
Indoor-Fan Contactor
Indoor-Fan Relay
Thousand Circular Mils
Liquid Line Solenoid
National Electrical Code
(U.S.A. Standard)
— Heating Relay (fieldsupplied 24-v sealed coil,
10 va maximum rating)
— Reversing Valve
— Terminal Block
Factory Wiring
Field Wiring

—
—
—
—
—
—
—
—

No. 16
No. 14

Fig. 20 — Field Wiring, One 2-Stage Thermostat — 38AH044-084 Dual-Circuit Units

28

Internal 33CSUCE-06 relay contacts are rated for 1 amp/24 vac.

*To control heating device and provide automatic indoorfan operation on heating.
†Jumper removed only when separate 24-v transformer power source is used to power the 33CSUCE-06
relay pack.
**Field-supplied.
NOTES:
1. Liquid line solenoid valves LLS-A1 and A2 are used
for solenoid drops.
2. Solenoid drop is a safety feature which prevents
refrigerant migration to the compressor during
the OFF cycle. It is recommended on all systems
and required on systems where piping exceeds
75 ft (22.9 m) in length.
3. The 33CSUCE-01 relay pack requires 10 va.
4. Factory wiring is in accordance with NEC; field modifications or additions must be in compliance with
all applicable codes.
5. Wiring for field power supply must be rated 75 C
minimum. Use copper, copper-clad aluminum, or
aluminum conductors. Maximum incoming wire size
for each terminal block is 500 kcmil.
6. Terminal blocks are for external field control connections. Control connections are to be Class 1
wiring.
7. Field-supplied components (IFC, LLS-A1, and
LLS-A2) must have a maximum sealed coil rating
of 30 va each (0.25 amp at 120 vac and 0.13 amp

8.
9.
10.
11.

at 230 vac). Thermostats must have a minimum pilot
duty rating of 300 va (2.5 amps at 120 vac and
1.3 amps at 230 vac).
Replacement of factory wires must be with type
105 C wire or its equivalent.
Field-supplied liquid line solenoid valves installed at
the evaporator are required on all units.
Units have 175 va of power available for fieldinstalled accessories.
To minimize voltage drop, the following wire sizes are
recommended:
LENGTH —
Ft (M)
Up to 50
(15.2)
50-75
(15.2-22.9)
More Than 75
(22.9)

INSULATED WIRE — AWG
(35 C Minimum)
No. 18

LEGEND

AWG
CR
HD
IFC
IFR
kcmil
LLS
NEC
R
RV
TB

—
—
—
—
—
—
—
—

American Wire Gage
Control Relay
Heating Device
Indoor-Fan Contactor
Indoor-Fan Relay
Thousand Circular Mils
Liquid Line Solenoid
National Electrical Code
(U.S.A. Standard)
— Heating Relay (fieldsupplied 24-v sealed coil,
10 va maximum rating)
— Reversing Valve
— Terminal Block
Factory Wiring
Field Wiring

No. 16
No. 14

Fig. 21 — Field Wiring, One 2-Stage Thermostat — 38AH044-084 Optional Single-Circuit Units
29

Internal 33CSUCE-06 relay contacts are rated for 1 amp/24 vac.

*To control heating device and provide automatic indoorfan operation on heating.
†Jumper removed only when separate 24-v transformer power source is used to power the 33CSUCE-06
relay pack.
**Field-supplied.
NOTES:
1. Liquid line solenoid valve LLS-A1 is used for solenoid drop
on circuit A. Liquid line solenoid valve LLS-B1 is used for
solenoid drop for circuit B.
2. Solenoid drop is a safety feature which prevents refrigerant
migration to the compressor during the OFF cycle. It is recommended on all systems and required on systems where
piping exceeds 75 ft (22.9 m) in length.
3. The 33CSUCE-06 relay pack requires 10 va.
4. Factory wiring is in accordance with NEC; field modifications
or additions must be in compliance with all applicable codes.
5. Wiring for field power supply must be rated 75 C minimum. Use copper, copper-clad aluminum, or aluminum conductors. Maximum incoming wire size for each terminal block
is 500 kcmil.
6. Terminal blocks are for external field control connections. Control connections must be Class 1 wiring.
7. Field-supplied components (IFC, LLS-A1, and LLS-B1) must
have a maximum sealed coil rating of 30 va each (0.25 amp
at 120 vac and 0.13 amp at 230 vac). Thermostats must have
a minimum pilot duty rating as follows:
38AH

VA
(Ea Stage)

094

275

104

325

AMPS

VAC

2.29
1.15
2.70
1.35

120
240
120
240

8. Replacement of factory wires must be with
type 105 C wire or its equivalent.
9. Field-supplied liquid line solenoid valves installed at the evaporator are required on all
units.
10. Units 38AH094 has 140 va and unit 38AH104
has 130 va of power available for fieldinstalled accessories.
11. To minimize voltage drop, the following wire
sizes are recommended:
LENGTH —
Ft (M)
Up to 50
(15.2)
50-75
(15.2-22.9)
More Than 75
(22.9)

INSULATED WIRE —
AWG
(35 C Minimum)
No. 18

AWG
CR
HD
IFC
IFR
kcmil
LLS
NEC
R
RV
TB

LEGEND
American Wire Gage
Control Relay
Heating Device
Indoor-Fan Contactor
Indoor-Fan Relay
Thousand Circular Mils
Liquid Line Solenoid
National Electrical Code
(U.S.A. Standard)
— Heating Relay (fieldsupplied 24-v sealed coil,
10 va maximum rating)
— Reversing Valve
— Terminal Block
Factory Wiring
Field Wiring

—
—
—
—
—
—
—
—

No. 16
No. 14

Fig. 22 — Field Wiring, One 2-Stage Thermostat — Units 38AH094 and 104
30

Internal 33CSUCE-06 relay contacts are rated for 1 amp/24 vac.

*Jumper removed only when separate 24-v transformer power source is used to power the 33CSUCE-06
relay pack.
†Field-supplied.
NOTES:
1. Liquid line solenoid valves LLS-A1 and A2 are used
for solenoid drop on Module 124A or 134A on circuit A. Liquid line solenoid valves LLS-B1 and B2
are used for solenoid drop for Module 124B or 134B.
Solenoid drop is a safety feature which prevents
refrigerant migration to the compressor during
the OFF cycle. It is recommended on all systems
and required on systems where piping exceeds
75 ft (22.9 m) in length.
2. Disconnect black wire from CR2 terminal 6; cap loose
end and secure. Connect new field-supplied wire
from CR2 terminal 6 to TB3 terminal 1 on module
124B or 134B.
3. The 33CSUCE-06 relay pack requires 10 va.
4. Factory wiring is in accordance with NEC; field modifications or additions must be in compliance with
all applicable codes.
5. Wiring for field power supply must be rated 75 C
minimum. Use copper, copper-clad aluminum, or
aluminum conductors. Maximum incoming wire size
for each terminal block is 500 kcmil.
6. Terminal blocks (TB3) are for external field control
connections. Control connections must be Class 1
wiring.

7. Field-supplied components (IFC, LLS-A1,A2, and
LLS-B1,B2) must have a maximum sealed coil
rating of 30 va each (0.25 amp at 120 vac and
0.13 amp at 230 vac). Thermostats must have a
minimum pilot duty rating of 300 va (2.5 amps at
120 vac).
8. Replacement of factory wires must be with type
105 C wire or its equivalent.
9. Field-supplied liquid line solenoid valves installed
at the evaporator are required on all units.
10. Units have 175 va of power available for fieldinstalled accessories.
11. To minimize voltage drop, the following wire sizes
are recommended:

LENGTH —
Ft (M)
Up to 50
(15.2)
50-75
(15.2-22.9)
More Than 75
(22.9)

INSULATED WIRE — AWG
(35 C Minimum)
No. 18
No. 16

LEGEND
AWG — American Wire Gage
C
— Compressor Contactor
CCPS — Capacity Control Pressure
Switch
CR
— Control Relay
HD
— Heating Device
IFC
— Indoor-Fan Contactor
IFR
— Indoor-Fan Relay
kcmil — Thousand Circular Mils
LLS
— Liquid Line Solenoid
NEC — National Electrical Code
(U.S.A. Standard)
R
— Heating Relay (fieldsupplied 24-v sealed coil,
10 va maximum rating)
RV
— Reversing Valve
SDR — Solenoid Drop Relay
TB
— Terminal Block
TR
— Timer Relay
Factory Wiring
Field Wiring

No. 14

Fig. 23 — Field Wiring, One 2-Stage Thermostat — Units 38AH124 and 134
31

32
*Field-supplied.

LEGEND
AHMS — Air Handler Motor
Starter
AUX
— Auxiliary
C
— Compressor Contactor
FU
— Fuse
GND
— Equipment Ground
IFC
— Indoor Fan Control
kcmil — Thousand Circular Mils
LLS
— Liquid Line Solenoid
NEC
— National Electrical Code
(U.S.A. Standard)

SDR
TB
TBX

— Solenoid Drop Relay
— Terminal Block
— Terminal Block for Variable
Air Volume Units
TM
— Timer Motor
TR
— Timer Relay
TRAN — Transformer
U
— Unloader Solenoid
Factory Wiring
Field Wiring

NOTES:
1. Factory wiring is in accordance with NEC; field modifications or additions must be in compliance with all applicable codes.
2. Wiring for field power supply must be rated 75 C minimum. Use copper, copper-clad aluminum, or aluminum conductors. Maximum
incoming wire size for each terminal block is 500 kcmil.
3. Terminal blocks TB3 and TB4 are for external field control connections. Control connections are to be Class 1 wiring.
4. Field-supplied components (IFC, LLS-A, and LLS-B) must have a maximum sealed coil rating of 30 va each (.25 amp at 120 vac, .13 amp at
230 vac). AHMS IFC-AUX must have a minimum pilot duty rating of
200 va (1.7 amps at 120 vac, 0.9 amps at 230 vac) each.
5. Replacement of factory wires must be with type 105 C wire or its
equivalent.
6. Field-supplied liquid line solenoid valves installed at the evaporator are
required on all units.
7. Units have 175 va of power available for field-installed accessories.

Fig. 24 — Field Wiring, Single ModuPanel™ Control, 38AH044-084 Dual-Circuit Units

33
*Field-supplied.

LEGEND
AHMS — Air Handler Motor
Starter
AUX
— Auxiliary
C
— Compressor Contactor
FU
— Fuse
GND
— Equipment Ground
IFC
— Indoor Fan Control
kcmil — Thousand Circular Mils
LLS
— Liquid Line Solenoid
NEC
— National Electrical Code
(U.S.A. Standard)

SDR
TB
TBX

— Solenoid Drop Relay
— Terminal Block
— Terminal Block for
Variable Air Volume
Units
TM
— Timer Motor
TR
— Timer Relay
TRAN — Transformer
U
— Unloader Solenoid
Factory Wiring
Field Wiring

NOTES:
1. Factory wiring is in accordance with NEC; field modifications or additions must be in compliance with all applicable codes.
2. Wiring for field power supply must be rated 75 C minimum. Use copper, copper-clad aluminum, or aluminum conductors. Maximum in coming wire size for each terminal block is 500 kcmil.
3. Terminal blocks TB3, TBX1, and TBX2 are for external field control connections. Control connections are to be Class 1 wiring.
4. Field-supplied components (IFC, LLS-A1, and LLS-A2) must have a
maximum sealed coil rating of 30 va each (0.25 amp at 120 vac,
13 amp at 230 vac). AHMS IFC-AUX must have minimum pilot duty
rating of 400 va each (3.4 amps at 120 vac, 1.8 amps at 230 vac) each.
5. Replacement of factory wires must be with type 105 C wire or its
equivalent.
6. Field-supplied liquid line solenoid valves installed at the evaporator are
required on all units.
7. Control has 175 va of power available for field-installed accessories.

Fig. 25 — Field Wiring, Single ModuPanel™ Control, 38AH044-084 Optional Single-Circuit Units

*Field-supplied.
NOTES:
1. Factory wiring is in accordance with NEC. Field modifications
or additions must be in compliance with all applicable codes.
2. Wiring for field power supply must be rated 75 C minimum. Use
copper, copper-clad aluminum, or aluminum conductors. Maximum incoming wire size for each terminal block is 500 kcmil.
3. Terminal blocks TB3, TB4, TBX1, and TBX2 are for external
field control connections. Control connections are to be
Class 1 wiring.
4. Field-supplied components (IFC, LLS-A1, A2, B1, and B2) must
have a maximum sealed coil rating of 30 va each (0.25 amp at
120 vac, 0.13 amp at 230 vac). AHMS IFC-AUX contact must
have minimum pilot duty rating of 325 va each (2.7 amps at
120 vac, 1.4 amps at 230 vac).
5. Replacement of factory wires must be with type 105 C wire or
its equivalent.
6. Field-supplied liquid line solenoid valves installed at the evaporator are required on all units.
7. Control has 25 va of power available for field-installed
accessories.

AHMS
AUX
C
FU
GND
IFC
kcmil
LLS
NEC

—
—
—
—
—
—
—
—
—

LEGEND
SDR
Air Handler Motor Starter
TB
Auxiliary
TBX
Compressor Contactor
Fuse
Equipment Ground
TM
Indoor Fan Control
TR
Thousand Circular Mils
TRAN
Liquid Line Solenoid
U
National Electrical Code
(U.S.A. Standard)

— Solenoid Drop Relay
— Terminal Block
— Terminal Block for Variable
Air Volume Units
— Timer Motor
— Timer Relay
— Transformer
— Unloader Solenoid
Factory Wiring
Field Wiring

Fig. 26 — Field Wiring, Single ModuPanel™ Control, Unit 38AH094
34

*Field-supplied.
NOTES:
1. Factory wiring is in accordance with NEC. Field modifications or
additions must be in compliance with all applicable codes.
2. Wiring for field power supply must be rated 75 C minimum. Use
copper, copper-clad aluminum, or aluminum conductors. Maximum incoming wire size for each terminal block is 500 kcmil.
3. Terminal blocks TB3, TB4, TBX1, and TBX2 are for external field
control connections. Control connections are to be Class 1 wiring.
4. Field-supplied components (IFC, LLS-A1, A2, B1, and B2) must
have a maximum sealed coil rating of 30 va each (0.25 amp at
120 vac, 0.13 amp at 230 vac). AHMS IFC-AUX contact must have
minimum pilot duty rating of 375 va each (3.1 amps at 120 vac,
1.6 amps at 230 vac).
5. Replacement of factory wires must be with type 105 C wire or its
equivalent.
6. Field-supplied liquid line solenoid valves installed at the evaporator are required on all units.
7. Control has 35 va of power available for field-installed accessories.

AHMS
AUX
C
FU
GND
IFC
kcmil
LLS
NEC
SDR

LEGEND
TB
Air Handler Motor Starter
TBX
Auxiliary
Compressor Contactor
Fuse
Equipment Ground
TM
Indoor Fan Control
TR
Thousand Circular Mils
TRAN
Liquid Line Solenoid
U
National Electrical Code
(U.S.A. Standard)
— Solenoid Drop Relay
—
—
—
—
—
—
—
—
—

Fig. 27 — Field Wiring, Single ModuPanel™ Control, Unit 38AH104
35

— Terminal Block
— Terminal Block for
Variable Air Volume
Units
— Timer Motor
— Timer Relay
— Transformer
— Unloader Solenoid
Factory Wiring
Field Wiring

*Field-supplied.
NOTES:
1. Factory wiring is in accordance with NEC. Field modifications or
additions must be in compliance with all applicable codes.
2. Wiring for field power supply must be rated 75 C minimum. Use
copper, copper-clad aluminum, or aluminum conductors. Maximum incoming wire size for each terminal block is 500 kcmil.
3. Terminal blocks TB3 and TBX1 are for external field control connections. Control connections are to be Class 1 wiring.
4. Field-supplied components (IFC, LLS-A1 and A2) must have a maximum sealed coil rating of 30 va each (0.25 amp at 120 vac,
0.13 amp at 230 vac). AHMS IFC-AUX contact must have minimum pilot duty rating of 400 va each (3.4 amps at 120 vac,
1.8 amps at 230 vac).
5. Replacement of factory wires must be with type 105 C wire or its
equivalent.
6. Field-supplied liquid line solenoid valves installed at the evaporator are required on all units.
7. Units have 175 va of power available for field-installed
accessories.

LEGEND

AHMS
AUX
C
FU
GND
IFC
kcmil
LLS
NEC

—
—
—
—
—
—
—
—
—

Air Handler Motor Starter
Auxilliary
Compressor Contactor
Fuse
Equipment Ground
Indoor Fan Control
Thousand Circular Mils
Liquid Line Solenoid
National Electrical Code
(U.S.A. Standard)

SDR
TB
TBX

— Solenoid Drop Relay
— Terminal Block
— Terminal Block for Variable
Air Volume Units
TM
— Timer Motor
TR
— Timer Relay
TRAN — Transformer
U
— Unloader Solenoid
Factory Wiring
Field Wiring

Fig. 28 — Field Wiring, Single ModuPanel™ Control, Units 38AH124 and 134
36

Table 15 — Main Power Connection and Control Circuit Wiring
Electrical
Characteristics
(V-Ph-Hz)
208/230-3-60
460-3-60
575-3-60
230-3-50
380-3-60
380/415-3-50
346-3-50

MAIN POWER CONNECTION
Qty
Qty
Terminal
Parallel
Blocks
Conductors*
1
6

CONTROL CIRCUIT
Max Wire
Size
(kcmil)
500

Control Power
(V)

Safety Circuit
(V)

115†

24

1

3

500

115†

24

1

6

500

230

24

1

3

500

230

24

1

3

500

200

24

LEGEND
kcmil — Thousand Circular Mils
*Conductors are from the safety disconnect.
†Control power is accomplished with a step-down transformer where primary voltage is field voltage.

2. Backseat (open) compressor suction and discharge shutoff valves. Close valves one turn to allow refrigerant pressure to reach the test gages.
3. Open liquid line service valves.
4. Check tightness of all electrical connections.
5. Oil should be visible in the compressor sight glasses.
See Fig. 29. An acceptable oil level in the compressor
is from 1⁄8 to 1⁄3 of sight glass. Adjust the oil level as
required. No oil should be removed unless the crankcase heater has been energized for at least 24 hours. See
Preliminary Oil Charge section on page 38, for Carrierapproved oils.
6. Electrical power source must agree with unit
nameplate.

Step 5 — Install Accessories
LOW-AMBIENT OPERATION
Units 38AH044-084, 124, and 134 — If operating temperatures below 55 F (13 C) are expected, Motormastert III fan
motor control is recommended. Refer to separate installation instructions for low-ambient operation guidelines.
Units 38AH094 and 104 — If operating temperatures below
45 F (7 C) are expected, Motormaster III fan motor control
is recommended. Refer to separate installation instructions
for low-ambient operation guidelines.
MISCELLANEOUS ACCESSORIES — For applications
requiring special accessories, the following packages are
available: condenser coil hail guard package, gage panel,
unloader package, unloader conversion kits, sound reduction package, condenser coil protective grilles, compressor
security grilles, ModuPanel™ control, and thermostat transformer relay package.

Crankcase heaters on all units are wired into the
control circuit, so they are always operable as long
as the main power supply disconnect is on (closed),
even if any safety device is open. Compressor heaters must be on for 24 hours prior to the start-up of
any compressor.

PRE-START-UP
IMPORTANT: Before beginning Pre-Start-Up or StartUp, review Start-Up Checklist at the back of this publication. The Checklist assures proper start-up of a unit
and provides a record of unit condition, application requirements, system information, and operation at initial start-up.

7. Crankcase heaters must be firmly locked into compressors, and must be on for 24 hours prior to start-up.
8. Fan motors are 3-phase. Check rotation of fans during
first start-up check. Fan rotation is clockwise as viewed
from top of unit. If fan is not turning clockwise, reverse
2 of the power wires.
9. Check compressor suspension. On units 38AH044-084,
124, and 134, snubber washers (for noise suppression)
can be moved with finger pressure. On units 38AH094
and 104, rails allow compressors to float freely on compressor rail springs.
10. On 38AH074,084 single-circuit units and Module
38AH134B, ensure that the packaging block located between the oil equalization tube and the compressor crossbrace has been removed.

Do not attempt to start the air-conditioning system until
following checks have been completed.

System Check
1. Check all system components, including the airhandling equipment. Consult manufacturer’s instructions. If the unit has field-installed accessories, be sure
all are properly installed and wired correctly. Refer to
unit wiring diagrams.

37

DISCHARGE
GAS THERMOSTAT

PRESSURE RELIEF
VALVE

CYLINDER
HEADS

SIGHT
GLASS

OIL PRESSURE SWITCH AND
CAPACITY CONTROL
PRESSURE SWITCH CAPILLARIES

RAIL

CRANKCASE
HEATER

MUFFLER

OIL
EQUALIZER
LINE

HIGHPRESSURE
SWITCH

FAN CYCLING
DISCHARGE GAS
PRESSURE SWITCH THERMOSTAT

LOWPRESSURE
SWITCH

SIGHT
GLASS

MOUNTING
SPRING
(HIDDEN)

NOTE: Units 38AH044-084 and 38AH124, 134 compressors are pan
mounted. Units 38AH094 and 104 compressors are mounted on rails.

Fig. 29 — 06E Compressors, Typical

8. If any leaks are detected, evacuate and dehydrate as previously outlined in Step 3 — Make Refrigerant Piping
Connections, page 14.

START-UP
Compressor crankcase heaters must be on for 24 hours
before start-up. To energize the crankcase heaters, set the
space thermostat above the ambient so there will be no demand for cooling. Close the field disconnect and turn on the
fan circuit breakers. Leave the compressor circuit breakers
off/open. The crankcase heaters are now energized.

Preliminary Oil Charge — Each compressor is factory charged with oil (see Table 3A, 3B, 4A, or 4B). When
oil is checked at start-up, it may be necessary to add or remove oil to bring it to the proper level. One recommended
oil level adjustment method is as follows:

Preliminary Checks

ADD OIL — Close suction shutoff valve and pump down
crankcase to 2 psig (14 kPa). (Low-pressure cutout must be
jumped.) Wait a few minutes and repeat until pressure remains steady at 2 psig (14 kPa). Remove oil fill plug above
the oil level sight glass, add oil through plug hole, and replace plug. Run compressor for 20 minutes and check oil
level.

1. Ensure that compressor service valves are backseated.
2. Verify that each compressor on units 38AH044-084, 124,
and 134 floats freely on its mounting springs. Verify that
each compressor on units 38AH094 and 104 floats freely
on its rails.
3. Check that electric power supply agrees with unit nameplate data.
4. Verify that compressor crankcase heaters are securely in
place.
5. Check that compressor crankcase heaters have been on at
least 24 hours.
6. Note that compressor oil level is visible in the sight glass.
7. Recheck for leaks using same procedure as previously outlined in Step 3 — Make Refrigerant Piping Connections,
page 14.

IMPORTANT: For units with 2 compressors per refrigeration circuit, both compressors must be running
to adjust the oil level. Two oil level equalizer lines
between compressors distribute the oil to each
compressor.

38

compressor B1. Start-up of compressor B1 is delayed from
12 seconds to 51⁄2 minutes. (Circuit B of unit 38AH094 has
only one compressor.)
Each circuit’s lead compressor start-up is controlled by
the unit control timer. The circuit’s lag compressor start-up
is controlled by the D-D2 timer contacts and capacity
control pressure switches (CCPSs) which monitor compressor suction pressure. The circuit’s lag compressor will start
approximately 21⁄2 minutes after a call for cooling if compressor pressure is above CCPS set point.

NOTE: Use only Carrier approved compressor oil. Approved sources are: Petroleum Specialties Inc. (Cryol 150A),
Texaco, Inc. (Capella WF-32-150), and Witco Chemical Co.
(Suniso 3GS). Do not reuse oil that has been drained out, or
oil that has been exposed to atmosphere.
REMOVE OIL — Pump down compressor to 2 psig
(14 kPag). Loosen the 1⁄4-in. (6.4-mm) pipe plug at the compressor base and allow the oil to seep out past the threads of
the plug.
NOTE: The crankcase will be slightly pressurized. Do not
remove the plug, or the entire oil charge will be lost.

38AH124,134 UNITS — Start-up of the lead circuit
(Module 124A or 134A) lead compressor A1 (Table 16) is
delayed from 12 seconds to 51⁄2 minutes from the time the
call for cooling is initiated by TC1. Lag compressor A2 is
controlled by D-D2 timer contacts and capacity control pressure switches (CCPSs) which monitor compressor suction
pressure. The lag compressor starts approximately 21⁄2 minutes after the lead compressor starts if the suction pressure
is above the CCPS set point.
After the lead circuit (Module 124A or 134A) lead compressor A1 (Table 16) starts, close the TC2 thermostat to start
the lag circuit (Module 124B or 134B) lead compressor (A1).
Lag circuit compressor A1 start-up is delayed from 12 seconds to 51⁄2 minutes from the time the call for cooling is
initiated by TC2. Lag compressor A2 is controlled by D-D2
timer contacts and CCPSs which monitor compressor suction pressure. Lag compressor A2 starts approximately 21⁄2
minutes after lead compressor A1 starts if the suction pressure is above the CCPS set point.

Small amounts of oil can be removed through the oil pump
discharge connection while the compressor is running.

Preliminary Charge — Refer to GTAC II (General Training Air Conditioning), Module 5, Charging, Recovery,
Recycling, and Reclamation for charging procedures. Using
the liquid charging method and charging by weight procedure, charge each circuit with the amount of R-22 listed in
Table 3A, 3B, 4A, or 4B.

Never charge liquid into the low-pressure side of system. Do not overcharge. During charging or removal of
refrigerant, be sure indoor-fan system is operating.

Start Unit — The field disconnect is closed, the fan circuit breaker is closed, and the space thermostats are set above
ambient so that there is no demand for cooling. Only the
crankcase heaters are energized.
Close the compressor circuit breakers and then reset both
space thermostats below ambient so that a call for stage one
cooling is ensured. Lead refrigeration circuit thermostat TC1 must be set to call for cooling at a lower temperature than lag refrigeration circuit thermostat TC2.
See Table 16 for lead/lag circuits on all units. Now set TC2
for cooling.

Adjust Refrigerant Charge
Never charge liquid into the low-pressure side of system. Do not overcharge. During charging or removal of
refrigerant, be sure indoor-fan system is operating.
With all fans operating, and all compressors on the circuit being serviced operating at full capacity, adjust the
refrigerant charge in accordance with the unit charging charts
located on the inside of the control box doors and in
Fig. 30-43. Charge vapor into compressor low-side service
port located above oil pump crankshaft housing. Measure
pressure at the liquid line service valve, making sure a Schrader
depressor is used if required. Also, measure liquid line temperature as close to the liquid service valve as possible. Add
charge until the pressure and temperature conditions of the
charging chart curve are met. If liquid pressure and temperature point fall above curve, add charge. If liquid pressure
and temperature point fall below curve, reduce the charge
until the conditions match the curve.
If the sight glass at location A (Fig. 11 and 12) is cloudy,
check refrigerant charge again. Ensure all fans and compressors on the circuit being serviced are operating. Also
ensure maximum allowable liquid lift has not been
exceeded.
If the sight glass at location A is clear and the sight
glass at location B is cloudy, a restriction exists in the
line between the 2 sight glasses. Check for a plugged filter
drier or partially open solenoid valve. Replace or repair, as
needed.

NOTE: Do not use circuit breakers to start and stop the compressor except in an emergency.
38AH044-084 DUAL-CIRCUIT UNITS — Start-up of lead
compressor A1 (Table 16) will be delayed from 12 seconds
to 51⁄2 minutes from the time the call for cooling is initiated
by TC1. After the lead compressor starts, close the TC2 thermostat to start lag circuit compressor B1. Compressor B1
will start a minimum of 60 seconds after thermostat TC2 is
closed.
38AH044-084 OPTIONAL SINGLE CIRCUIT UNITS —
Start-up of lead compressor A1 (Table 16) is delayed from
12 seconds to 51⁄2 minutes from the time the call for cooling
is initiated by TC1. Closure of TC2 will actuate LLS-A2.
Lag compressor A2 is controlled by D-D2 timer contacts and
capacity control pressure switches (CCPSs) which monitor
compressor suction pressure. The lag compressor starts approximately 21⁄2 minutes after the lead compressor starts if
the suction pressure is above the CCPS set point.
38AH094,104 UNITS — Start-up of lead circuit A,
compressor A1 (Table 16) is delayed from 12 seconds to
51⁄2 minutes from the time the call for cooling is initiated.
After lead circuit A, compressor A1 starts, close refrigeration circuit thermostat TC2 to start lag circuit B, lead

39

Table 16 — Index of Lead/Lag Circuits and Compressors
UNIT
38AH

044-084
STD

044-084
OPT

094

104

124

134

LEAD CIRCUIT
Compressor, Lead
Compressor; Lag

A
A1
*

A
A1
A2

A
A1
A2

A
A1
A2

LAG CIRCUIT
Compressor, Lead
Compressor; Lag

B
B1
*

†

B
B1
*

B
B1
B2

Module
124A
A1
A2
Module
124B
A1
A2

Module
134A
A1
A2
Module
134B
A1
A2

LEGEND
OPT — Optional Single-Circuit Units
STD — Standard Dual-Circuit Units
*Circuit has only one compressor.
†Units have only one circuit.

electrically actuated unloaders are installed, energize the solenoid to unload the compressor. Recheck the compressor
oil level as described in Check Compressor Oil Level above.
Return unloader to original setting after checks are
complete.
UNITS 38AH094,104 — For this minimum load check, the
lead compressor (A1, B1) of each refrigeration circuit is unloaded. See Table 16. The lag compressor (A2, B2 [38AH104
only]) of each refrigeration circuit must not be operating.
Unload the compressor(s) by turning the control set point
adjustment nut counterclockwise until the adjustment nut stops.
The unloader is now at 0 psig (0 kPag) set point. If electrically actuated unloaders are installed, energize the solenoid
to unload the compressor.
Return unloader to original setting after checks are
complete.

Check Compressor Oil Level — After adjusting the
refrigerant charge, allow each circuit to run fully loaded for
20 minutes. Running oil level should be 1⁄8 to 1⁄3 up on the
sight glass. Stop the compressors at the field power supply
disconnect and check the crankcase oil level. Add oil only if
necessary to bring the oil into view in the sight glass. If oil
is added, run the circuit for an additional 10 minutes, then
stop and check oil level. If the level remains low, check the
piping system for proper design for oil return; also, check
the system for leaks.
If the initial check shows too much oil (too high in the
sight glass) remove oil to proper level. See Preliminary Oil
Charge for proper procedure for adding and removing oil.
When the above checks are complete, repeat the procedure with the unit operating at minimum load conditions.
UNITS 38AH044-084,124, AND 134 — For this minimum
load check, run the lead compressor of each refrigeration circuit fully unloaded with the lag compressor not operating.
Unload the compressor(s) by turning the control set point
adjustment nut counterclockwise until the adjustment nut
stops. The unloader is now at 0 psig (0 kPag) set point. If

Final Checks — Ensure all safety controls are operating, control panel covers are on, and the service panels are
in place.

40

Fig. 30 — Charging Chart — Unit 38AH044; 50/60 Hz — Dual Circuit

Fig. 31 — Charging Chart — Unit 38AH054; 50/60 Hz — Dual Circuit

41

Fig. 32 — Charging Chart — Unit 38AH064; 50/60 Hz — Dual Circuit

Fig. 33 — Charging Chart — Unit 38AH074; 50/60 Hz — Dual Circuit

42

Fig. 34 — Charging Chart — Unit 38AH084; 50/60 Hz — Dual Circuit

Fig. 36 — Charging Chart — Unit 38AH054;
50/60 Hz — Optional Single Circuit

Fig. 35 — Charging Chart — Unit 38AH044;
50/60 Hz — Optional Single Circuit

43

Fig. 37 — Charging Chart — Unit 38AH064;
50/60 Hz — Optional Single Circuit

Fig. 38 — Charging Chart — Unit 38AH074;
50/60 Hz — Optional Single Circuit

Fig. 39 — Charging Chart — Unit 38AH084;
50/60 Hz — Optional Single Circuit

44

Fig. 40 — Charging Chart — Unit 38AH094; 50/60 Hz

Fig. 41 — Charging Chart — Unit 38AH104; 50/60 Hz

Fig. 42 — Charging Chart — Modules 124A, 124B,
and 134A; 50/60 Hz

Fig. 43 — Charging Chart — Module 134B;
50/60 Hz
45

The heater is held in place by a clip and bracket and must be
tightly connected since exposure to the air causes the heater
to burn out. Each heater is wired into the compressor control
circuit through a relay which energizes only when the compressor is off. The heater keeps the oil at a temperature that
prevents excessive absorption of refrigerant during shutdown periods.
Energize the crankcase heaters when the unit is not running except during prolonged shutdown or servicing. Energize the heaters at least 24 hours before restarting the unit
after prolonged shutdown.
TIME GUARDt FUNCTION — This function prevents compressors from short-cycling.

SERVICE
ELECTRIC SHOCK HAZARD
Turn off all power to unit before servicing.
The ON-OFF switch on control panel
does not shut off control power; use field
disconnect.

Coil Cleaning — Clean the coils with a vacuum cleaner,
compressed air, water, or a non-wire bristle brush.
Refrigerant Circuit
LEAK TESTING — Units are shipped with a holding charge
of R-22 (see Table 3A, 3B, 4A, or 4B) and should be under
sufficient pressure to conduct a leak test. If there is no pressure in the system, introduce enough nitrogen to search
for the leak. Repair the leak using good refrigeration practices. After leaks are repaired, system must be evacuated and
dehydrated using methods described in GTAC II , Module 4,
System Dehydration.
REFRIGERANT CHARGE (Refer to Table 3A, 3B, 4A, or
4B) — At the liquid line connection point on each circuit is
a factory-installed liquid line service valve. On each
valve is a 1⁄4-in. Schrader connection for charging liquid
refrigerant.
Charging with Unit Off and Evacuated — Close liquid
line service valve before charging. Weigh in charge shown
in Table 3A, 3B, 4A, or 4B. Open liquid line service valve;
start unit and allow it to run several minutes fully loaded.
Check for a clear sight glass. Be sure clear condition is liquid and not vapor. Complete charging the unit in accordance
with Start-Up, Adjust Refrigerant Charge, page 39.
Charging with Unit Running — If charge is to be added while
unit is operating, it is necessary to have all condenser fans
and compressors operating. It may be necessary to block condenser coils at low-ambient temperatures to raise condensing pressure to approximately 280 psig (1931 kPag) to turn
all condenser fans on. Do not totally block a coil to do this.
Partially block all coils in uniform pattern. Charge
vapor into compressor low-side service port located above
oil pump crankshaft housing. Charge each circuit until sight
glass shows clear liquid.

Fan Motor Protection — Fan motors are protected
by a single circuit breaker for all motors.
Head Pressure Control — Head pressure control reduces condenser capacity under low-ambient conditions. This
is achieved by fan cycling control (standard, all units) and
Motormastert III control accessory (field installed).
FAN CYCLING — All condensing units have standard provision for fully automatic intermediate season head pressure
control through fan cycling (see Table 17).
38AH044-084 Dual-Circuit Units — Fans no. 3 and 4 are
cycled by pressure control on all units. On 38AH074 and
084, fans no. 5 and 6 are also cycled by pressure control.
38AH044-084 Optional Single Circuit Units — Fans no. 3
and 4 are cycled by pressure control on all units. On 38AH074
and 084, fans no. 5 and 6 are cycled by an air-temperature
switch located in the bottom shelf of the control box.
Units 38AH094,104 — Fans no. 3 through 6 are cycled by
pressure control.
Units 38AH124,134 — Fans no. 3 and 4 on each unit module are cycled by pressure control. On module 134B only,
fans no. 5 and 6 are cycled by an air-temperature switch located in the bottom shelf of the control box.
Pressure control is achieved via a fan cycling pressure switch
located on the cylinder head of the unit or circuit lead compressor (see Fig. 29).
The air-temperature switch used to control fans no. 5 and
6 on 38AH074,084 optional single-circuit units and on module 134B is closed and cycles the fans on when the ambientair temperature is above 70 F (21 C).

Troubleshooting — Refer to Troubleshooting chart located at back of book.

Oil Pressure Safety Switch (OPS) — An oil pres-

Table 17 — Fan Cycling Control — Psig (kPag)

sure safety switch for each of the independent refrigerant
circuits shuts off the compressor in that circuit if oil pressure
is not established at start-up or maintained during operation.
If the OPS stops the unit, determine and correct the cause
before restarting the unit. Failure to do so constitutes equipment abuse and could affect the warranty.

Control by Pressure*
Switch Opens
Switch Closes

± 10 (69)
160 (1103)
255 (1758)

*On all units, fans no. 3 and 4; also on unit 38AH074, 084 (dualcircuit units only) and 38AH094,104, fans no. 5 and 6.
NOTE: Fans no. 1 and 2 are noncycling. Units 38AH074,084 optional
single-circuit units and module 134B fans no. 5 and 6 are
cycled by an air-temperature switch which operates above 70 F
(21 C) ambient-air temperature.

Compressor Motor Protection
CIRCUIT BREAKER — A manual reset, calibrated trip circuit breaker for each compressor protects against overcurrent. Do not bypass connections or increase size of circuit
breaker for any reason. If trouble occurs, determine the cause
and correct it before resetting the breaker.
DISCHARGE GAS THERMOSTAT — A sensor in the
cylinder head of each compressor (Fig. 29) shuts down the
compressor if excessively high discharge gas temperature is
sensed. If the discharge gas thermostat shuts the unit down,
it may be reset by the thermostat or power disconnect switch.
CRANKCASE HEATER (See Fig. 29) — Each compressor
has an electric crankcase heater located in the bottom cover.

38AH044-064,
Modules 124A, 124B,
134A

46

38AH074-104,
Module 134B

38AH094,104 — Capacity control is achieved by a pressureactuated cylinder bank unloader on the lead compressor
(A1, B1) on each of the 2 refrigeration circuits. As the cooling load decreases and the suction pressure drops, the unloader actuates at the pre-set suction pressure and unloads
the cylinder bank. (See Fig. 44 and Table 20.) The unloading
of the compressor cylinder bank has no effect on the operation of the circuit lag compressor (A2, B2 [except 38AH094,
circuit B]) which is controlled by fixed setting capacity control pressure switches (CCPSs) as follows:

Winter Start Control — A 21⁄2-minute low-pressure switch
(LPS) bypass function in the timer prevents nuisance LPS
trips during start-up in low-ambient conditions.

High-Pressure Switch — This switch has nonadjustable settings. Figure 29 shows connection on a cylinder head.
See Table 18 for pressure switch settings.
NOTE: High-pressure switch must be removed from cylinder head before removing compressor from the unit.
TO CHECK — Slowly close the discharge shutoff valve until the compressor shuts down. This should be at approximately 426 psig (2935 kPag). Slowly open the valve. When
the pressure drops to approximately 320 psig (2205 kPag),
the pressure switch resets. To reenergize the control circuit,
manually switch the fan circuit breaker off and then on. The
compressor starts again under Time Guardt controls.

CCPS 1
CCPS 2

CUT-IN —
Psi (kPa)
83 (572)
80 (551)

CUTOUT —
Psi (kPa)
63 (531)
53 (365)

CCPS — Capacity Control Pressure Switch

Low-Pressure Switch — The low-pressure switch (LPS)
has fixed nonadjustable settings. It is located at the pump
end of the compressor above the bearing head. See Table 18
for pressure switch settings.
TO CHECK — Slowly close the suction cut-off valve and
allow the compressor to shut down. This should occur at
approximately 27 psig (186 kPag). Slowly open the valve.
The compressor restarts under Time Guard control when the
pressure builds to approximately 67 psig (462 kPag).

Pressure Relief — High-side pressure relief is provided by a fusible plug in the liquid line at the service valve.
For low-side pressure relief, a fusible plug is inserted in the
side of the accumulator (all units except 38AH044-084 dualcircuit, constant-volume units). See Fig. 45. The 38AH044084 dual-circuit, constant-volume units have a fusible plug
in the suction tubing. A pressure relief valve installed on the
compressor relieves at 450 psig (3102 kPag) (see Fig. 1-6).

Table 18 — Pressure Switch Settings,
Psig (kPag)
SWITCH
High
Low

CUTOUT
426 ± 7
(2935 ± 48)
27 ± 4
(186 ± 28)

CUT-IN
320 ± 20
(2205 ± 138)
67 ± 7
(462 ± 48)

Capacity Control
38AH044-084 DUAL-CIRCUIT UNITS — Capacity control is achieved by a pressure-actuated cylinder bank unloader on lead compressor A1. As the cooling load decreases
and the suction pressure drops, the unloader actuates at the
pre-set suction pressure and unloads the cylinder bank. (See
Fig. 44 and Table 19A.) The unloading of the compressor
cylinder bank has no effect on the operation of lag compressor B2, which is controlled by TC2.
38AH044-084 SINGLE-CIRCUIT UNITS AND MODULES 124A, 124B, 134A, AND 134B — Capacity control
is achieved by a pressure-actuated cylinder bank unloader
on lead compressor A1. See Table 16. As the cooling load
decreases and the suction pressure drops, the unloader
actuates at the pre-set suction pressure and unloads the cylinder bank. (See Fig. 44 and Table 19B and 20.) Lag compressor A2 is controlled by fixed setting capacity control pressure
switches (CCPSs) as follows:

CCPS 1
CCPS 2

CUT-IN —
Psi (kPa)
83 (572)
80 (551)

CUTOUT —
Psi (kPa)
63 (531)
53 (365)

Unloader Settings
Unload, psig (kPag)
Load, psig (kPag)

CCPS — Capacity Control Pressure Switch

56 (386)
76 (524)

*Unloader location.

Fig. 44 — Unloader Location and Settings

If suction pressure continues to drop after lead compressor A1 unloads and lag compressor A2 is operating, A2 will
stop operating when the suction pressure drops to the CCPS
cutout point.

47

Table 19A — One 2-Stage Thermostat Capacity
Control for 38AH044-084 Dual-Circuit Units
UNIT
38AH

044

054

064

074

084

QUANTITY OF LOADED
COMPRESSOR CYLINDERS
Circuit
Circuit
Total
A
B
4
4
8
2
4
6
4
0
4
2
0
2
4
6
10
2
6
8
2
4
6*
4
0
4
2
0
2
6
6
12
4
6
10
2
6
8*
6
0
6
4
0
4
2
0
2*
6
6
12
4
6
10
2
6
8*
6
0
6
4
0
4
2
0
2*
6
6
12
4
6
10
2
6
8*
6
0
6
4
0
4
2
0
2*

Table 20 — One 2-Stage Thermostat Capacity
Control for 38AH094-134 Units

SYSTEM
CAPACITY
(%)

UNIT
38AH

100
75
50
25
100
79
59
42
21
100
84
68
48
32
16
100
86
72
43
29
15
100
83
66
50
33
17

094

104

124

*Requires units with VAV (variable air volume) factory-supplied
option.
NOTE: Units have 2 independent refrigeration circuits. Circuit A is lead
circuit.

134

Table 19B — One 2-Stage Thermostat Capacity
Control for 38AH044-084 Optional Single-Circuit Units
UNIT
38AH
044

054

064

074

084

QUANTITY OF
LOADED CYLINDERS
8
6
4
2
10
8
6
6
4
2*
12
10
8
6
4
2†
12
10
8
6
4
2†
12
10
8
6
4
2†

QUANTITY OF LOADED
COMPRESSOR CYLINDERS
Ckt A
Ckt B
Total
10
6
16
10
4
14
10
2
12
10
0
10
8
0
8
6
0
6
4
0
4
10
12
22
8
12
20
8
10
18
10
6
16
6
6
12
6
4
10
0
6
6
4
0
4
0
4
4
2†
0
2
12
12
24
10
12
22
10
10
20
8*
10
18
6
10
16
6
8*
14
6
6
12
4
6
10
6
0
6
4
0
4
2*
0
2
12
12
24
10
12
22
10
10
20
8*
10
18
6
10
16
6
8*
14
6
6
12
4
6
10
6
0
6
4
0
4
2*
0
2

SYSTEM
CAPACITY
(%)
100
85
70*
55
44
33
22
100
91
82
73
55
45
27
18
18
9†
100
92
83
75*
67
58*
50
42
25
17
8*
100
92
83
75*
67
58*
50
42
25
17
8*

*Requires VAV (variable air volume) unit or accessory unloader(s) field
installed on circuit lead compressor. Lead compressor is identified in
Table 16, page 40.
†Requires field-installed accessory unloader on circuit lead compressor. Lead compressor is identified in Table 16, page 40.

SYSTEM
CAPACITY
(%)
100
75
50
25
100
81
60
56
37
19*
100
82
64
56
36
18
100
81
62
57
38
19
100
83
66
50
33
17

NOTES:
1. Temperatures calculated with the minimum number of fans operating per circuit.
2. See Table 16, page 40, for information on lead and lag circuits.

CONTROL SET POINT — Control set point (cylinder load
point) is adjustable from 0 to 85 psig (0 to 586 kPag).
To adjust the set point, turn the control set point adjustment nut clockwise to bottom stop. (See Fig. 46.) In this
position, load-up set point is 85 psig (586 kPag). Turn
adjustment counterclockwise to desired control set point.
Every full turn clockwise decreases the load-up set point by
7.5 psig (52 kPag).
PRESSURE DIFFERENTIAL — Pressure differential
(difference between cylinder load and unload points) is
adjustable from 6 to 22 psig (41 to 152 kPag). To adjust,
turn pressure differential adjustment screw counterclockwise to back stop position. The differential pressure is now
adjusted to 6 psig (41 kPag). Turn the adjustment screw clockwise to adjust the differential pressure. Every full clockwise
turn increases the differential by 1.5 psig (10 kPag).

*Requires accessory unloader on lead 06E-265 compressor (A1).
†Requires VAV (variable air volume) factory-installed option or accessory unloader.

48

CONDENSER
COIL

FUSIBLE
PLUG

SUCTION
LINE

ACCUMULATOR

DISCHARGE
LINE

COMPRESSOR RAIL

Fig. 45 — Accumulator and Fusible Plug

Timer Functions — (See Timer Cycle, Fig. 47.) Each
refrigeration circuit is controlled by an independent timer
which allows for the independent operation of each refrigeration circuit.

Fig. 46 — Pressure-Actuated Capacity Control Valve

NOTE: Unit 38AH044-084 optional single-circuit units have
one timer which controls the lead compressor. Lag compressor is controlled by CCPS (capacity control pressure switch).

CONTROL
Sequence of Operation — Units are controlled with
electromechanical components. Each refrigeration circuit
(except 38AH044-084 optional single-circuit units) is operated by an independent timer which controls the operation
sequence of each circuit.
On a call for cooling, first stage cooling thermostat TC1
closes. Condenser fans and timer (TM) are energized. After
approximately 7 seconds, timer contacts E-E1 close.
Approximately 12 seconds after TC1 closes, normally-open
timer contacts B-B1 close for 1 second. This energizes
compressor A1 contacts CA1 and starts the compressor. At
the same time, solenoid drop relays (SDRs) and liquid line
solenoid valve no. 1 (LLS-A for 38AH044-084 dual-circuit
units; LLS-A1 for all other units) open, and timer relay
no. 1 (TR2) is energized. Normally open TR2 contacts close,
completing a circuit around B-B1 and through compressor
A1 contactors to maintain compressor operation when B-B1
contacts open. Contacts E-E1 remain closed for approximately 40 seconds to bypass the oil pressure switch (OPS).
If oil pressure is insufficient when contacts E-E1 open, the
compressor stops, the timer cycles off, and the control circuit locks out. At start-up, timer contacts D-D1 are closed,
bypassing low-pressure relay contacts LPR-A for 21⁄2 minutes. This provides a winter start-up feature.
Approximately 21⁄2 minutes after TC1 closes, timer contacts D-D1 open and D-D2 close. If pressure is insufficient
to close the low-pressure switch, the low-pressure switch
relay is open, the compressor shuts down, and the Time Guard
control is initiated. (Time Guard control prevents compressor from restarting for 5 minutes after the demand for cooling is satisfied.)

SWITCH A — The timer is energized through contacts A-A1
or A-A2. This establishes the Time Guardt function which
prevents compressor short-cycling. Start of compressor is
delayed approximately 5.5 minutes after shutdown.
SWITCH B — The compressor is initially energized through
contacts B-B1.
SWITCH D — Contacts D-D1 provide a 21⁄2-minute bypass
of the low-pressure switch at start-up for winter-start control. On 38AH044-084 optional single-circuit units, contacts
D-D2 control start-up of compressor A2.
SWITCH E — Contacts E-E1 provide a 40-second bypass
of the oil pressure switch at start-up. If oil pressure does not
build to the required minimum pressure in 40 seconds, the
compressor shuts down and the control circuit locks out.
On 38AH044-084 dual-circuit and 38AH094,104 units, lag
circuit B start-up is delayed 60 seconds after a call for cooling is made to the circuit. This prevents compressor(s) in
both lead and lag circuits from starting at the same time.

Control Circuit Reset — The control circuit locks out
if the unit shuts down because of low oil pressure, high
discharge gas temperature (DGT), or excessive high-side pressure. To reset the control circuit, open and close the fan
circuit breaker (FCB). This resets the timer, and the unit
restarts under Time Guard control. At start-up, if the lowpressure switch (LPS) does not close after 21⁄2 minutes, the
unit shuts down. When the pressure builds enough for the
LPS to cut in, the control circuit is energized automatically
and start-up proceeds under Time Guard control.

49

38AH044-084 DUAL-CIRCUIT UNITS; 38AH094,104 —
If circuit A operation is insufficient for the cooling requirements, the thermostat second stage TC2 closes to bring circuit B on-line for cooling. This circuit follows the same sequence of operation as the lead circuit, except a
60-second time delay relay (TDR) delays compressor start-up
for 60 seconds after the call for cooling.
38AH044-084 OPTIONAL SINGLE-CIRCUIT UNITS: MODULES 124A, 124B, 134A, AND 134B
NOTE: This sequence of operation assumes that 2 thermostats control units 38AH124 or 134 with one thermostat controlling each module.
If compressor A1 is insufficient for the cooling requirements, the thermostat second stage closes, which opens the
liquid line solenoid valve LLS-A2. Compressor A2 starts only
after D-D2 contacts in the timer close and the suction pressure is sufficient to close the capacity control switches.
ALL UNITS — When the fan switch is set for automatic
(AUTO) operation, the indoor-fan contactor (IFC) is cycled
with the lead compressor. If the fan switch is set for continuous (CONT), the IFC is energized as long as the unit
power is on.

NOTE: Black denotes closed contacts.

Fig. 47 — Timer Cycle

Unit Control Box — (See Fig. 48.) Viewed facing compressors, the control box is at left end of the unit. All incoming power enters through the control box. The control
box contains power components and electronic controls. Outer
panels are hinged and latched for easy opening. Remove screws
to remove inner panels. Outer panels can be held open for
service and inspection by using door retainer on each panel.
Remove bottom pin from door retainer assembly, swing retainer out horizontally, and engage pin in one of the retainer
ears and the hinge assembly.

Restart After Stoppage by Safety Control — The
high-pressure switch, compressor discharge gas thermostats,
and the oil pressure switch must be reset manually by breaking the control power supply at any of the following points:
control circuit fuse, fan motor circuit breaker, or the thermostat. Restart follows the Time Guardt control delay.
Stoppage by low-pressure switch results in Time Guard
control delay, then unit attempts normal restart.
The compressor motor overcurrent protectors are manualreset circuit breakers. Reset of control circuit may also be
necessary.

Condenser Fans — Each fan is supported by a formed
wire mount bolted to fan deck and covered with a wire guard.
The exposed end of fan motor shaft is protected from weather
by grease. If fan motor must be removed for service or replacement, be sure to regrease fan shaft, and reinstall fan
guard. For proper performance, fan should be 7⁄8 in.
(22 mm) below top of venturi on the fan deck to top of
the fan hub for 60-Hz units, and 1⁄2 in. (13 mm) for 50-Hz
units. (See Fig. 49.) Tighten set screws to 15 ± 1 ft-lbs
(20 ± 1.3 N-m). Figure 49 shows proper position of mounted
fan.

Independent Refrigerant Circuit Controls — Each
refrigeration circuit is controlled by independent circuitry.
Therefore, it is possible to maintain partial cooling capability even if one compressor is inoperable.
NOTE: The 38AH044-084 optional single-circuit units do
not have independent control circuitry.

IMPORTANT: Check for proper fan rotation (clockwise viewed from above). If necessary to reverse, switch
leads.

50

TRANSFORMERS

FAN CONTACTORS
TIMERS

TIME-DELAY
RELAY
COMPRESSOR
CIRCUIT
BREAKERS

FAN CIRCUIT
BREAKER
TERMINAL
BLOCKS

OIL PRESSURE
SWITCHES

FUSE
HOLDERS

TERMINAL
BLOCKS

COMPRESSOR
CONTACTORS

Fig. 48 — Unit Control Box

Required Compressor Modification for 38AH044084 Optional Single-Circuit Units, When Compressor A1 is Out — To maintain unit operation, compressor no.1 must be operable. If it is not operable, the following
temporary modifications must be made to keep the unit
running:
1. Change the oil pressure switch connections from compressor A1 to compressor A2.
2. Connect compressor A2 into the Time Guardt circuit as
compressor A1 was originally.
3. Open compressor A1 circuit breaker.
NOTE: Make sure the crankcase heaters are energized when
compressors are off.

NOTE: Fan rotation is clockwise when viewed from top of unit.

Fig. 49 — Condenser Fan Adjustment

51

Compressor Removal — Access to the pump end

Compressor Replacement — Perform the following:

of the compressor is from the compressor side of the unit.
Access to the motor end of the compressor is from the inside
of the unit. All compressors can be removed from the compressor side of the unit.

1. Reverse procedure in Compressor Removal section to end
of Step 4.
2. Reinstall service valves and safety switches, and tighten
to torques as listed:

IMPORTANT: All compressor mounting hardware and
support brackets removed during servicing must be reinstalled prior to start-up.

Torque

Compressor(s)

Tighten discharge valves to —
20-25 ft-lbs ( 27- 34 N-m)
06E-250
80-90 ft-lbs (109-122 N-m)
06E-265,275,299
Tighten suction valves to —
80- 90 ft-lbs (109-122 N-m)
06E-250
90-120 ft-lbs (122-163 N-m)
06E-265,275,299
Tighten the following fittings as specified —
60 ft-lbs (81 N-m)
Discharge Gas Thermostat
120 in.-lbs (13.5 N-m)
High-Pressure Switch, FanCycling Pressure Switch
120 in.-lbs (13.5 N-m)
Low-Pressure Switch

1. Disconnect power to unit; lockout power to compressor.
2. Close suction and discharge service valves.
3. Relieve refrigerant pressure into a refrigerant recovery
system.
4. Remove:
a. Fan-cycling pressure switch (FCPS)
b. High-pressure switch
c. Low-pressure switch
d. Oil-pressure switch
e. Discharge gas temperature switch.
5. Disconnect power wires at terminal box and disconnect
conduit.
6. Disconnect wires from crankcase heater.
7. Disconnect service valves from compressor.
NOTE: On 38AH044-084 optional single-circuit units and
units with 2 compressors per circuit, disconnect both oil
equalizer lines located on the motor barrel and on the oil
pump sump.
8. Units 38AH044-084, 124, and 134:
a. Remove 4 large screws securing compressor mounting pan to unit base rail.
b. Slide compressor (on mounting pan) to outside of unit
frame; support and/or lower to ground.
c. Unbolt compressor from mounting pan and remove.
9. Units 38AH094, 104:
a. Remove 4 large screws securing compressor to the compressor rails.
b. Lift compressor off mounting bolts and remove.

3. Leak-check and evacuate system, reclaim refrigerant.
4. Recharge system per pre-start-up and start-up sequences.
Recheck oil levels.
5. Energize crankcase heater for 24 hours prior to restart of
system.
OIL CHARGE — (Refer to Table 3A, 3B, 4A, or 4B.) All
units are factory charged with oil. Acceptable oil level for
each compressor is from 1⁄8 to 1⁄3 of sight glass (see Fig. 29,
page 38).
When additional oil or a complete charge is required, use
only Carrier-approved compressor oil.
Approved oils are:
Petroleum Specialties, Inc. — Cryol 150A (factory oil charge)
Texaco, Inc.
— Capella WF-32-150
Witco Chemical Co.
— Suniso 3GS
COMPRESSOR
06E-250
06E-265
06E-275
06E-299

OIL REQUIRED
Pts
L
17
8.0
21
9.9
21
9.9
19
9.0

Do not reuse drained oil, and do not use any oil that has
been exposed to atmosphere.
Adjust oil level in accordance with Start-Up, Preliminary
Oil Charge, page 38.

52

TROUBLESHOOTING
PROBLEM
COMPRESSOR DOES NOT RUN
Contactor Open
1. Power off.
2. Fuses blown in field power circuit.

SOLUTION

1. Restore power.
2. After finding cause and correcting, replace with correct
size fuse.
3. Check secondary fuse(s); replace with correct type and
size. Replace transformer if primary windings receiving
power.
4. Check thermostat setting.
5. Check timer for proper operation; replace if defective.
6. Check for excessive compressor current draw. Reset
breaker; replace if defective.
7. Reset lockout circuit at thermostat or circuit breaker.
8. Check for refrigerant undercharge, obstruction of indoor
airflow, or whether compressor suction shutoff valve is
fully open. Make sure liquid line solenoid valve(s) is
open.
9. Check for refrigerant overcharge, obstruction of outdoor
airflow, air in system or whether compressor discharge
valve is fully open. Be sure outdoor fans are operating
correctly.
10. Check for open condition. Allow for reset. Replace if
defective.
11. Tighten all connections.
12. See 06E compressor service literature.

3. No control power.
4. Thermostat circuit open.
5. Multi-function timer not operating.
6. Compressor circuit breaker tripped.
7. Safety device lockout circuit active.
8. Low-pressure switch open.

9. High-pressure switch open.

10. Discharge gas temperature switch open.
11. Loose electrical connections.
12. Compressor stuck.
Contactor Closed
1. Compressor leads loose.
2. Motor windings open.
3. Single phasing.

1. Check connections.
2. See 06E compressor service literature.
3. Check for blown fuse. Check for loose connection at
compressor terminal.

COMPRESSOR STOPS ON HIGH-PRESSURE SWITCH
Outdoor Fan On
1. High-pressure switch faulty.
2. Airflow restricted.
3. Air recirculating.
4. Noncondensables in system.
5. Refrigerant overcharge.
6. Line voltage incorrect.
7. Refrigerant system restrictions.
Outdoor Fan Off
1. Fan slips on shaft.
2. Motor not running.
3. Motor bearings stuck.
4. Motor overload open.
5. Motor burned out.
COMPRESSOR CYCLES ON LOW-PRESSURE SWITCH
Indoor-Air Fan Running
1. Filter drier plugged.
2. Expansion valve power head defective.
3. Low refrigerant charge.
Airflow Restricted
1. Coil iced up.
2. Coil dirty.
3. Air filters dirty.
4. Dampers closed.
Indoor-Air Fan Stopped
1. Electrical connections loose.
2. Fan relay defective.
3. Motor overload open.
4. Motor defective.
5. Fan belt broken or slipping.

1.
2.
3.
4.
5.
6.
7.

Replace switch.
Remove obstruction.
Clear airflow area.
Purge and recharge as required.
Purge as required.
Consult power company.
Check or replace filter drier, expansion valve, etc. Check
that compressor discharge valve is fully open.

1.
2.
3.
4.
5.

Tighten fan hub setscrews.
Check power and capacitor.
Replace bearings.
Check overload rating. Check for fan blade obstruction.
Replace motor.

1. Replace filter drier.
2. Replace power head.
3. Add charge. Check low-pressure switch setting.

53

1.
2.
3.
4.

Check refrigerant charge.
Clean coil fins.
Clean or replace filters.
Check damper operation and position.

1.
2.
3.
4.
5.

Tighten all connections.
Replace relay.
Power supply.
Replace motor.
Replace or tighten belt.

TROUBLESHOOTING (cont)
PROBLEM
COMPRESSOR STOPS ON OIL PRESSURE SWITCH
1. Oil level too low or too high.
2. Compressor is short cycling.

3. Crankcase heater off.
4.
5.
6.
7.
8.

Low refrigerant charge.
Refrigerant floodback.
Evaporator coil is blocked or iced.
Evaporator fan not operating.
Distributor and/or TXV too large.

9. Suction riser too large.
10. Defective oil pressure switch.
11. Plugged oil pump inlet screen.
12. Faulty oil pump drive segment.
13. Worn oil pump.
14. Worn compressor bearings.
COMPRESSOR RUNNING BUT COOLING INSUFFICIENT
Suction Pressure Low
1. Refrigerant charge low.
2. Head pressure low.
3. Air filters dirty.
4. Expansion valve power head defective.
5. Indoor coil partially iced.
6. Indoor airflow restricted.
Suction Pressure High
1. Unloaders not functioning.
2. Compressor valve defective.
3. Heat load excessive.
UNIT OPERATES TOO LONG OR CONTINUOUSLY
1. Low refrigerant charge.
2. Control contacts fused.
3. Air in system.
4. Partially plugged expansion valve or filter drier.
SYSTEM IS NOISY
1. Piping vibration.
2. Compressor noisy.
COMPRESSOR LOSES OIL
1. Leak in system.
2. Crankcase heaters not energized during shutdown.
3. Improper interconnecting piping design.
FROSTED SUCTION LINE
1. Expansion valve admitting excess refrigerant.
HOT LIQUID LINE
1. Shortage of refrigerant due to leak.
2. Expansion valve opens too wide.
FROSTED LIQUID LINE
1. Restricted filter drier.
COMPRESSOR WILL NOT UNLOAD
1. Defective unloader.
2. Defective capacity control solenoid valve (if used).
3. Miswired capacity control liquid line solenoid (if used).
4. Weak, broken, or wrong valve body spring.
COMPRESSOR WILL NOT LOAD
1. Miswired capacity control liquid line solenoid (if used).
2. Defective capacity control solenoid valve (if used).
3. Plugged strainer (high side).
4. Stuck or damaged unloader piston or piston ring(s).

SOLUTION
1. Check oil level requirements; adjust oil level until sight
glass is filled 1⁄8 to 1⁄3 when running.
2. Check for
a) Thermostat location and operation.
b) Safety device lockout circuit operation.
c) End-of-cycle control and timer operation.
d) Low-pressure switch and relay operation.
3. Check relay operation; replace crankcase heater(s), if
defective.
4. Adjust charge as required.
5. Adjust TXV superheat.
6. Check and correct as required.
7. Check and correct as required.
8. Check sizing at design conditions; change if incorrect
for current application.
9. Check line sizing at minimum design condition; change
piping if incorrect.
10. Check switch for proper operation; check capillary lines
for plugged lines.
11. Clean oil pump screen.
12. Replace drive segment.
13. Replace bearing head assembly.
14. Replace compressor; see 06E service instructions.

1. Add refrigerant.
2. Check refrigerant charge.
Check outdoor-air fan thermostat settings.
3. Clean or replace filters.
4. Replace power head.
5. Check low-pressure setting.
6. Remove obstruction.
1. Check unloader adjustments.
Check unloader setting.
2. See 06E compressor service literature.
3. Check for open doors or windows in vicinity of fan coil.
1.
2.
3.
4.

Add refrigerant.
Replace control.
Purge and evacuate system.
Clean or replace.

1. Support piping as required.
2. Check valve plates for valve noise. Replace compressor
if bearings are worn.
1. Repair leak.
2. Check wiring and relays. Check heater and replace if
defective.
3. Check piping for oil return. Replace if necessary.
1. Adjust expansion valve.
1. Repair leak and recharge.
2. Adjust expansion valve.
1. Remove restriction or replace.
1.
2.
3.
4.

Replace unloader.
Replace valve.
Rewire correctly.
Replace spring.

1.
2.
3.
4.

Rewire correctly.
Replace valve.
Clean or replace strainer.
Clean or replace the necessary parts.

Copyright 1998 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. 563-704
Printed in U.S.A.
Form 38AH-15SI
54
10-98
Replaces: 38AH-14SI
Tab 3a

START-UP CHECKLIST
A. Preliminary Information
OUTDOOR: MODEL NO.

SERIAL NO.

INDOOR: AIR HANDLER MANUFACTURER
MODEL NO.

SERIAL NO.

ADDITIONAL ACCESSORIES

B. Pre-Start-Up
OUTDOOR UNIT
IS THERE ANY SHIPPING DAMAGE?

(Y/N)

IF SO, WHERE:

WILL THIS DAMAGE PREVENT UNIT START-UP?

(Y/N)

CHECK POWER SUPPLY. DOES IT AGREE WITH UNIT?
HAS THE GROUND WIRE BEEN CONNECTED?

(Y/N)

(Y/N)

HAS THE CIRCUIT PROTECTION BEEN SIZED AND INSTALLED PROPERLY?

(Y/N)

ARE THE POWER WIRES TO THE UNIT SIZED AND INSTALLED PROPERLY?

(Y/N)

HAVE COMPRESSOR HOLDDOWN BOLTS BEEN LOOSENED?

(Y/N)

CONTROLS
ARE THERMOSTAT(S) AND INDOOR FAN CONTROL WIRING
CONNECTIONS MADE AND CHECKED?
(Y/N)
ARE ALL WIRING TERMINALS (including main power supply) TIGHT?

(Y/N)

HAVE CRANKCASE HEATERS BEEN ENERGIZED FOR 24 HOURS?

(Y/N)

INDOOR UNIT
HAS WATER BEEN PLACED IN DRAIN PAN TO CONFIRM PROPER DRAINAGE?
ARE PROPER AIR FILTERS IN PLACE?

(Y/N)

(Y/N)

HAVE FAN AND MOTOR PULLEYS BEEN CHECKED FOR PROPER ALIGNMENT?
DO THE FAN BELTS HAVE PROPER TENSION?

(Y/N)

(Y/N)

PIPING
ARE LIQUID LINE SOLENOID VALVES LOCATED AT THE EVAPORATOR COILS AS REQUIRED?
HAVE LEAK CHECKS BEEN MADE AT COMPRESSORS, CONDENSERS, EVAPORATORS,
TXVs (Thermostatic Expansion Valves) SOLENOID VALVES, FILTER DRIERS, AND FUSIBLE PLUGS
WITH A LEAK DETECTOR?
(Y/N)
LOCATE, REPAIR, AND REPORT ANY LEAKS.
HAVE ALL COMPRESSOR SERVICE VALVES BEEN FULLY OPENED (BACKSEATED)?
ARE THE COMPRESSOR OIL SIGHT GLASSES SHOWING ABOUT ⁄ FULL?

(Y/N)

(Y/N)

12

CHECK VOLTAGE IMBALANCE
LINE-TO-LINE VOLTS:

AB

V

AC

(AB + AC + BC)/3 = AVERAGE VOLTAGE =

V

BC

V

V

MAXIMUM DEVIATION FROM AVERAGE VOLTAGE =

V

VOLTAGE IMBALANCE = 100 X (MAX DEVIATION)/(AVERAGE VOLTAGE) =
IF OVER 2% VOLTAGE IMBALANCE, DO NOT ATTEMPT TO START SYSTEM!
CALL LOCAL POWER COMPANY FOR ASSISTANCE.

CL-1

%

(Y/N)

CHECK EVAPORATOR FAN SPEED AND RECORD.
CHECK CONDENSER FAN SPEED AND RECORD.
AFTER AT LEAST 10 MINUTES RUNNING TIME, RECORD THE FOLLOWING MEASUREMENTS:
COMP A1

COMP A2

COMP B1

COMP B2

OIL PRESSURE
SUCTION PRESSURE
SUCTION LINE TEMP
DISCHARGE PRESSURE
DISCHARGE LINE TEMP
ENTERING CONDENSER AIR TEMP
LEAVING CONDENSER AIR TEMP
EVAP ENTERING AIR DB TEMP
EVAP ENTERING AIR WB TEMP
EVAP LEAVING AIR DB TEMP
EVAP LEAVING AIR WB TEMP
COMPRESSOR AMPS (L1)
COMPRESSOR AMPS (L2)
COMPRESSOR AMPS (L3)
CHECK THE COMPRESSOR OIL LEVEL SIGHT GLASSES; ARE THE SIGHT GLASSES SHOWING
(Y/N)
OIL LEVEL AT 1⁄8 TO 1⁄3 FULL?

NOTES:

Copyright 1998 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. 563-704
Printed in U.S.A.
Form 38AH-15SI
CL-2
10-98
Replaces: 38AH-14SI
Tab 3a

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - CUT ALONG DOTTED LINE
CUT ALONG DOTTED LINE

C. Start-Up



---

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