Carrier 38AKS028-044 User Manual
Air-Cooled Condensing Units
Installation, Start-Up and
Service Instructions
CONTENTS
38AKS028-044
50/60 Hz
Page
SAFETY CONSIDERATIONS ...................1
BEFORE INSTALLATION .....................1-3
Rigging ......................................1
Placing Unit .................................3
Mounting Unit ...............................3
Compressor Mounting ........................3
INSTALLATION .............................3-12
Refrigerant Piping Connections ...............3
Liquid Line Solenoid Drop Control ............3
Filter Drier and Moisture Indicator ............3
Receiver .....................................4
Piping Procedure ............................4
Power Supply ................................6
Power Wiring ................................6
START-UP ................................13-17
Initial Check ................................13
Leak Test and Dehydration ..................13
Preliminary Charge ..........................13
Start Unit ...................................13
Charge System .............................13
Operation ...................................13
Control Module (CM) ........................13
Bypass Relay (BPR) .........................17
Time-Delay Relay (TDR) .....................17
Sequence of Operation ......................17
Complete Unit Stoppage .....................17
SERVICE ..................................17-20
Access for Servicing ........................17
Fan Adjustment .............................19
Oil Charge ..................................19
Liquid Shutoff/Charging Valve ...............19
Capacity Control ............................19
Oil Pressure Safety Switch (OPS) ............20
Compressor Protection ......................20
High-Pressure Switch .......................20
Low-Pressure Switch ........................20
Winter Start Control .........................20
Head Pressure Control ......................20
TROUBLESHOOTING ........................21
START-UP CHECKLIST .....................CL-1
SAFETY CONSIDERATIONS
Installing, starting up, and servicing air-conditioning 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 (Fig. 1).
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.
• Follow all safety codes.
• Wear safety glasses and work gloves.
• Keep, quenching cloth and fire extinguisher nearby when
brazing.
• Use care in handling, rigging, and setting bulky
equipment.
• See Table 1A or 1B for physical data.
ELECTRIC SHOCK HAZARD
Open all remote disconnects before
servicing this equipment.
BEFORE INSTALLATION
Rigging —
above the unit. Use 2-in. (50 mm) OD pipe or hooks in lifting holes. Rig with 4 cables and spreader bars. All panels
must be in place when rigging. See rigging label on unit for
details concerning shipping weights, distance between lifting holes, center of gravity, and spreader bar dimensions.
See Fig. 2.
If overhead rigging is not possible, place unit on skid or
pad for rolling or dragging. When rolling, use minimum of
3 rollers. When dragging, pull the pad. Do not apply force
to the unit. When in final position, raise from above to lift
unit off pad.
Preferred method is with spreader bars from
All panels must be in place when rigging.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
Tab 3a
PC 111 Catalog No. 533-820 Printed in U.S.A. Form 38A-5SI Pg 1 7-94 Replaces: 38AK-3SI
Table 1A — Physical Data — English
UNIT 38AKS 028 034 044
COMPRESSOR Reciprocating Semi-Hermetic
No. ...Type 1...06E9265 1...06E9275 1...06E9299
No. Cyls (ea)...Speed, Rpm (60/50 Hz) 6...1750/1460
Capacity Steps 3
Oil Charge*, Pt 20.0 20.0 19.0
Oil Pressure Switch (psi)
Set Points — Cutout 6 6 2
Differential — Cut-in 14 Max.
Crankcase Heater (watts) 180
Protection See Note
Capacity Control (Psig) Suction Pressure Unloader(s)
No. 1 Unloader Settings
Load 76 76 76
Unload 58 58 58
No. 2 Unloader Settings
Load 78 78 78
Unload 60 60 60
REFRIGERANT CHARGE, R-22
Approximate lb 30.5 43.5 65
COIL STORAGE
(at 125 F liquid temperature
and 80% full), lb
CONDENSER FANS, Type Propeller Type, Direct Driven
No. ...Diameter, in. 2...30 3...30
Total Airflow, Cfm 15,700 23,700
Speed, Rpm 60/50 Hz 1140/950
CONDENSER COIL, Type Horizontal Plate Fin
Rows...Fins/in. 2...19 3...17 3...17
Total Face Area, sq ft 39.2 39.2 58.4
*See Service, Oil Charge, for Carrier-approved oil.
NOTE: Circuit breaker is in main power circuit.
37.7 56.6 84.4
Table 1B — Physical Data — SI
UNIT 38AKS 028 034 044
COMPRESSOR Reciprocating Semi-Hermetic
No. ...Type 1...06E9265 1...06E9275 1...06E9299
No. Cyls (ea)...Speed, R/s (60/50 Hz) 6...29.2/24.3
Capacity Steps 3
Oil Charge*, L 9.4 9.4 9.0
Oil Pressure Switch (kPa)
Set Points — Cutout 41.4 6 13.8
Differential — Cut-in 96.5 Max.
Crankcase Heater (watts) 180
Protection See Note
Capacity Control (kPa) Suction Pressure Unloader(s)
No. 1 Unloader Settings
Load 524 524 524
Unload 400 400 400
No. 2 Unloader Settings
Load 538 538 538
Unload 414 414 414
REFRIGERANT CHARGE, R-22
Approximate, kg 13.8 19.7 29.5
COIL STORAGE
(at 52 C liquid temperature
and 80% full), kg
CONDENSER FANS, Type Propeller Type, Direct Driven
No. ...Diameter, mm 2...762 3...762
Total Airflow, L/s 7,400 11,200
Speed, R/s (60/50 Hz) 19.0/15.8 19.0/15.8
CONDENSER COIL, Type Horizontal Plate Fin
Rows...Fins/mm 2...1.34 3...1.49 3...1.49
Total Face Area, sq m 3.64 3.64 5.43
*See Service, Oil Charge, for Carrier-approved oil.
NOTE: Circuit breaker is in main power circuit.
17.1 25.7 38.3
2
Placing Unit — There must be 4 ft (1220 mm) for ser-
vice on all sides of unit, and a minimum of 8 ft (2440 mm)
clear air space above unit. For multiple units, allow 8 ft
(2440 mm) separation between units for airflow and service.
Mounting Unit — When unit is in proper location, use
of mounting holes in base rails is recommended for securing
unit to supporting structure or for mounting unit on vibration isolators, if required. Fasteners for mounting unit are
field supplied. Be sure to mount unit level to ensure proper
oil return to compressors.
Compressor Mounting — As shipped, compressor
is held down by 4 bolts. After unit is installed loosen each
bolt using nut indicated in Fig. 3 until flatwasher (3⁄8in.
[9.5 mm]) can be moved with finger pressure.
Fig. 1 — 38AKS Units
NOTES:
1. Use 2 in. OD (50 mm) pipe or hooks in lifting holes.
2. Rig with 4 cables and spread with 2 ‘‘D’’ long and two ‘‘A’’ long
2 x 4’s in. (50 x 100 mm) or equal.
3. Run the rigging cables to a central suspension point so that the
angle from the horizontal is not less than 45 degrees.
All panels must be in place when rigging.
MAX SHIP.
UNIT
38AKS
028 1924 872 81 2057 43.0 1092 28.0 711 73.5 1867
034 2115 960 81 2057 43.0 1092 28.0 711 73.5 1867
044 2797 1207 99 2515 49.0 1245 30.5 775 73.5 1867
WT
Lb Kg in. mm in. mm in. mm in. mm
LIFTING
HOLES
CENTER OF GRAVITY
‘‘A’’
‘‘B’’ ‘‘C’’
‘‘D’’
INSTALLATION
Refrigerant Piping Connections—
pend on length of piping required between condensing unit
and evaporator. See Table 2A or 2B. It is important to consider liquid lift and compressor oil return. Refer to Part 3 of
Carrier System Design Manual for line sizing information,
and Fig. 4 for recommended piping details.
Line sizes de-
Liquid Line Solenoid Drop Control — The factory-
supplied solenoid valve must be installed at the indoor unit
(fan coil) per Fig. 5, and wired per wiring label found on
unit. The solenoid assures that system refrigerant is in the
high-pressure side (condenser and liquid line) of the system
during the off cycle. Refrigerant migration is minimized.
Factory-supplied liquid line solenoid valve connecting sizes
7
⁄8-in. (22.2 mm) ODF for inlet and7⁄8-in. (22.2 mm)
are
ODM for outlet.
Failure to properly install liquid line solenoid at the indoor unit as described, without Carrier authorization, may
VOID warranty.
Filter Drier and Moisture Indicator — Every unit
should have a filter drier and a sight glass (moisture indicator) field installed. Select the filter drier for maximum unit
capacity and minimum pressure drop. Figure 5 shows recommended locations of filter drier(s) and sight glass. Complete the refrigerant piping from the evaporator to the condenser before opening the liquid and suction lines at the
condensing unit. One filter drier may be installed at location
A in Fig. 5, or 2 filter driers may be installed at locations B.
Fig. 2 — Rigging with Spreader Bars
(Field Supplied)
3
NOTE: All dimensions are in inches (mm).
Fig. 3 — Compressor Mounting
TXV — Thermostatic Expansion Valve
NOTES:
1. Suction line is connected to coil on same side as the entering air.
2. Lower section is first on and last off.
3. For more complete piping information, refer to Carrier System
Design Manual, Part 3.
Fig. 4 — Suction Line Piping to Unit
with 2 Section Coil Split
TXV — Thermostatic Expansion Valve
Fig. 5 — Liquid Line Solenoid Valve,
Filter Drier(s) and Sight Glass Locations
Receiver — No receiver is provided with the unit; it is
recommended that one not be used.
Piping Procedure — Do not remove run-around pipe
from suction and liquid line stubs until piping connections
are ready to be made. Pass nitrogen or other inert gasthrough
piping while brazing, to prevent formation of copper oxide.
Install field-supplied thermostatic expansion valve (TXV)
in liquid line ahead of each evaporator section. For 2-stage
cooling, the field-supplied capacity controlsolenoidusedmust
be wired to be opened by control from a 2-stage thermostat.
SUCTION PIPING AT EVAPORATOR AND TXV BULB
LOCATION (See Fig. 5) — The purpose of these recommendations is to achieve good mixing of the refrigerant leaving the evaporator suction header for proper sensing by the
TXV bulb.
1. A minimum of two 90° elbows must be installed up-
stream of the expansion valve bulb location.
2. The TXV sensing bulb should be located 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 throughthe riser
for high velocity. Enter the suction pipe sizing charts in
the CarrierSystemDesignManual at design tons and equivalent length (for 2° F [1.1° C] loss). If reading falls between 2 sizes on chart, choose the smaller pipe size.
Suction piping for the high velocity section should be
selected for about 0.5° F (0.3° C) friction loss. If a 2° F
(1.1° C) loss is allowed for the entire suction line, 1.5° F
(0.8° C) is left for the balance of the suction line, and it should
be sized on that basis. Check that the high-velocity sizing
is adequate for oil return up the riser.
If an oil return connection at the bottom of this suction
header is supplied with an evaporator, this connection must
be teed-in ahead of first mixing elbow. When the compressor is below the evaporator, the riser at the evaporator does
not have to extend as high as the top level. After a
15-diameter riser has been provided, the suction line may
elbow down immediately.
SAFETY RELIEF — Afusible plug is located on unit liquid
line before the liquid valve.
4
Table 2A — Refrigerant Piping Sizes — 60 Hz
SINGLE SUCTION RISERS
UNIT
38AKS
028
034
044
L—Liquid Line
S—Suction Line
16-25 (4.9-7.6) 26-50 (7.9-15.2) 51-75 (15.5-22.8) 76-100 (23.2-30.5) 101-200 (30.8-60.9)
LSL S L S L S L S
7
⁄
8
7
⁄
8
7
⁄
8
15⁄
21⁄
21⁄
8
8
8
7
⁄
8
7
⁄
8
7
⁄
8
*IMPORTANT — Requires a double suction riser, if evaporator is below condensing unit. See table below.
NOTE: Liquid and suction line sizes are OD (in.) Equivalent sizes in mm are listed below.
LENGTH OF INTERCONNECTING PIPING, FT (M)
21⁄8*
21⁄
21⁄
7
⁄
8
11⁄
7
⁄
8
8
8
8
21⁄8*
21⁄
8
25⁄8*1
7
⁄
8
11⁄
8
1
⁄
8
21⁄8*
21⁄
8
5
2
⁄
8
*1
DOUBLE SUCTION RISERS — 60 Hz
UNIT
38AKS
028 1
26-50 (7.9-15.2) 51-75 (15.5-22.8) 76-100 (23.2.-30.5) 101-200 (30.8-60.9)
ABCABC A B C A B C
3
⁄
8
15⁄
8
21⁄
8
034 —————— — — —1
044 ———1
NOTE: A, B, C dimensions relate to reference diagram.
LENGTH OF INTERCONNECTING PIPING, FT (M)
13⁄
8
15⁄
8
21⁄
5
⁄82
1
⁄82
8
5
⁄81
13⁄
8
5
⁄82
15⁄
8
1
⁄82
21⁄
8
5
⁄81
Table 2B — Refrigerant Piping Sizes — 50 Hz
SINGLE SUCTION RISERS
UNIT
38AKS
028
034
044
L—Liquid Line
S—Suction Line
*IMPORTANT — Requires a double suction riser, if evaporator is below condensing unit. See table below.
†For riser, use 1
16-25 (4.9-7.6) 26-50 (7.9-15.2) 51-75 (15.5-22.8) 76-100 (23.2-30.5) 101-200 (30.8-60.9)
LSL S L S L S L S
7
⁄
8
7
⁄
8
7
⁄
8
5
⁄8OD inches.
15⁄
21⁄8†
21⁄
8
8
7
⁄
8
7
⁄
8
7
⁄
8
NOTE: Liquid and suction line sizes are OD (in.) Equivalent sizes in mm are listed below.
LENGTH OF INTERCONNECTING PIPING, FT (M)
21⁄8*
21⁄8*
21⁄
7
⁄
8
7
⁄
8
8
11⁄
8
21⁄8*
21⁄8*1
25⁄8*1
7
⁄
8
1
⁄
8
1
⁄
8
21⁄8*
5
2
⁄
8
*1
5
2
⁄
8
*1
7
⁄
8
11⁄
8
1
⁄
8
13⁄
8
5
⁄82
5
⁄82
15⁄
8
1
⁄82
1
⁄82
7
⁄
8
1
⁄
8
1
⁄
8
21⁄8*
25⁄8*
5
2
⁄
8
*
21⁄
8
5
⁄
8
5
⁄
8
21⁄8*
5
2
⁄
8
*
5
2
⁄
8
*
DOUBLE SUCTION RISERS — 50 Hz
UNIT
38AKS
028 1
034 15⁄
26-50 (7.9-15.2) 51-75 (15.5-22.8) 76-100 (23.2.-30.5) 101-200 (30.8-60.9)
ABCABC A B C A B C
3
⁄
8
15⁄
8
21⁄
8
8
15⁄
8
21⁄
8
044 ———1
NOTE: A, B, C dimensions relate to reference diagram.
Unit Size Dimension — in. (mm)
028 15⁄8(41.3)
034 21⁄8(54.0)
044 21⁄8(54.0)
LENGTH OF INTERCONNECTING PIPING, FT (M)
13⁄
8
15⁄
8
5
⁄82
15⁄
8
21⁄
8
15⁄
8
21⁄
1
⁄82
8
5
⁄81
13⁄
8
15⁄
8
5
⁄82
15⁄
8
15⁄
8
1
⁄82
21⁄
8
21⁄
8
5
⁄81
13⁄
8
15⁄
8
5
⁄82
MAXIMUM LIQUID LIFT
UNIT 38AKS
028 76 23 66 20
034 67 20 60 18
044 76 23 66 20
EQUIVALENT SIZES IN MM
60 Hz 50 Hz
FtMFtM
in. mm
7
⁄
11⁄
13⁄
1
21⁄
2
8
8
8
5
⁄
8
8
5
⁄
8
22.2
28.6
34.9
41.3
54.0
66.7
15⁄
8
21⁄
8
1
⁄82
21⁄
8
25⁄
8
5
⁄
8
5
Power Supply — Electrical characteristics of available
power supply must agree with unit nameplate rating. Supply
voltage must be within limits shown in Table 3.
IMPORTANT:Operatinguniton improper supply voltage, orwithexcessivephaseimbalance,constitutes abuse
and mayaf fectCarrier warranty.SeeUnbalanced3-Phase
Supply Voltage, page 7.
Power Wiring — All power wiring must comply with
applicable localandnationalcodes.Install field-supplied branch
circuit fused disconnect(s) per NEC (National Electrical Code,
U.S.A.) of a type that can be locked OFF or OPEN. Disconnect(s) must be within sight from and readily accessible
from unit in compliance with NEC Article 440-14.
GENERAL WIRING NOTES
1. A crankcase heater is wired in the control circuit so it is
always operable as long as power supply disconnect is
on, even if any safety device is open or unit stop-start
switch is off. It is protected by a 5-amp circuit breaker in
control power.
2. The power circuit field supply disconnect should never be
open except when unit is being serviced or is to be down
for a prolongedperiod.Whenoperationisresumed, crankcase heater should be energized for 24 hours before startup. If unit is to be shut down for a prolonged period, it
is recommended that the suction and discharge valves be
closed to prevent an excessive accumulation of refrigerant in the compressor oil.
3. Power entry is one end only.
4. Maximum field wire sizes allowed by lugs on terminal
block are:
UNIT
38AKS
028 208/230-3-60
034
044
LEGEND
AWG — American Wire Gage
kcmil — Thousand Circular Mils
*All other units use 2/0 AWG (67.4 mm
V-Ph-Hz
208/230-3-60
230-3-50
208/230-3-60
230-3-50
2
).
WIRE
SIZE*
350 kcmil
5. Terminals for field power supply are suitable for copper,
copper-clad aluminum, or aluminum conductors. Insulation must be rated 167 F (75 C) minimum.
CONDENSER FANS— The fans must rotate counterclockwise when viewed from above. If necessary, correct direction of fan rotation by interchanging any 2 powerinput wires
at disconnect switch. Affix crankcase heater decal (located
in installer’s packet) to unit disconnect switch.
Table 3 — Electrical Data
60 HZ
UNIT
38AKS
500
028
034
044
028
034
044
CSA — Canadian Standards Association
FLA — Full Load Amps
ICF — Maximum InstantaneousCurrentFlow duringstarting(the point
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps (complies with National
MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps
UL — Underwriters’ Laboratories
200
600
100
500
200
600
100
500
200
600
100
UNIT
38AKS
800
300
900
800
300
900
800
300
900
inthestarting sequence wherethesum oftheLRA forthe starting compressor,plus the total FLA for allrunningfanmotors is
maximum).
Electrical Code [NEC, U.S.A.], Section 430-24)
3 Ph, 60 Hz
208/230
208/230
3 Ph, 50 Hz
LEGEND
Volts
380
460
575
380
460
575
230
380
460
575
Volts
230
346
400
230
346
400
230
346
400
Supplied*
Min. Max.
187
342
414
518
187
342
414
518
187
342
414
518
Supplied*
Min. Max.
198
311
342
198
311
342
198
311
342
UNIT COMPRESSOR FAN MOTORS
MCA
254
418
508
632
254
418
508
632
254
418
508
632
124.6
64.7
60.7
52.5
145.5
72.5
68.7
54.9
203.0
111.1
91.0
81.5
50 HZ
UNIT COMPRESSOR FAN MOTORS
MCA
254
380
400
254
380
400
254
380
400
109.0
64.9
60.5
120.2
76.1
68.5
150.6
112.6
90.8
MOCP
(Fuse)
200
110
100
80
250
125
110
90
350
175
150
125
MOCP
(Fuse)
175
100
100
200
125
110
250
175
150
*Units are suitable for use on electrical systems where voltage sup-
ICF RLA LRA FLA (ea) Qty
452.2
250.9
226.1
167.4
512.2
283.9
256.1
179.4
702.4
389.8
351.2
282.8
ICF RLA LRA FLA (ea) Qty
348.4
263.4
226.0
372.4
298.4
256.0
557.8
408.8
351.0
pliedtounit terminals isnotbelow orabovelisted minimum andmaximum limits.
89.8
45.5
43.6
36.5
106.5
52.6
50.0
38.5
147.5
79.5
65.4
57.1
76.9
44.9
43.6
85.9
53.9
50.0
105.1
79.5
65.4
446
247
223
164
506
280
253
176
690
382
345
276
342
259
223
366
294
253
545
400
345
6.2
3.9
3.1
3.4
6.2
3.9
3.1
3.4
6.2
3.9
3.1
3.4
6.4
4.4
3.0
6.4
4.4
3.0
6.4
4.4
3.0
2
2
2
2
2
2
2
2
3
3
3
3
2
2
2
2
2
2
3
3
3
6
FIELD CONNECTIONS
1. Main Power — Bring wires from the fused disconnect
switch through hole in bottom rail of unit to control box
12
(Fig. 6 and 7) and connect terminals , , and
line side of terminal block TB1 (see Fig. 8 and 9A
13
11
or 9B). To comply with NECArticle 440-14, the disconnect must be located within sight from and readily accessible from unit.
2. 24-v ControlPower—Unitshavesinglepointpower connections. Control circuit is directly connected internally
to unit. Maximum 24-v control circuit is 3 amps.
NOTE: Wire runs use the following insulated wire:
LENGTH
0-50 18 0.82
50-75 16 1.30
Over 75 14 2.08
AWG — American Wire Gage
*35 C minimum.
INSULATED WIRE SIZE*
AWG mm
2
3. Control Circuit Interlock — An airflow switch may be
installed in the indoor air handler to prevent unit from
running when indoor air is not flowing. This switch (no.
HR81JE001) is available from Service Parts Center, or
equivalent can be field supplied. This should be electrically interlocked in the control circuit, between thermo-
2
stat TC1 (stage 1, cooling) and terminal on TB3.
Y1
See Fig. 8 for typical field wiring. This is in the 24-v circuit. Wires must be run in conduit with ground wire.
4. Transformer Connections — See unit wiring label diagram, notes 1 and 2, located behind compressor compartment end access door.
IMPORTANT: Ensure power to the crankcase heater
is always on (except when servicing the unit). If circuit breakerinsideunitshutsdown the compressor,crankcase heater remains on.
UNBALANCED 3-PHASE SUPPLY VOLTAGE — Never
operate a motor where a phase imbalance in supply voltage
is greater than 2%. Use the following formula to determine
the percent voltage imbalance:
% Voltage Imbalance
= 100 x
max voltage deviation from average voltage
average voltage
Example: Supply voltage is 240-3-60.
AB = 243 v
BC = 236 v
AC = 238 v
Average Voltage =
243 + 236 + 238
3
= 239 volts
Determine maximum deviation from average voltage:
(AB) 243 − 239=4v
(BC) 239 − 236=3v
(AC) 239 − 238=1v
Maximum deviation is 4 v. Determine percent voltage
imbalance:
% Voltage Imbalance = 100 x
4
239
= 1.7%
This amount of phase imbalance is satisfactory as it is be-
low the maximum allowable 2%.
IMPORTANT: Contact your local electric utility company immediately if the supply voltage phase imbalance is more than 2%.
7
LEGEND
NEC — National Electrical Code
VAV — Variable Air Volume
NOTES:
1. There must beminimum(2440mm) 8 ft. clear air spaceabove
unit.
2. The approximate operating weight of the unit is:
50 AND 60 HZ
UNIT
38AKS028 1650 748
38AKS028C 1804 818
38AKS034 1803 818
38AKS034C 2009 911
3. A ‘‘C’’in the model number indicates unit has factory-installed
copper coil.
WT
(Lb)WT(Kg)
Fig. 6 — Dimensional Drawing, 38AKS028,034
8
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