Carrier 38AKS028 044 User Manual

38AKS028-044  
Air-Cooled Condensing Units  
50/60 Hz  
Installation, Start-Up and  
Service Instructions  
CONTENTS  
Page  
SAFETY CONSIDERATIONS  
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 1  
Installing, starting up, and servicing air-conditioning equip-  
ment can be hazardous due to system pressures, electrical  
components, and equipment location (roofs, elevated struc-  
tures, etc.).  
Only trained, qualified installers and service mechanics  
should install, start up, and service this equipment (Fig. 1).  
BEFORE INSTALLATION . . . . . . . . . . . . . . . . . . . . . 1-3  
Rigging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
Placing Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3  
Mounting Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3  
Compressor Mounting . . . . . . . . . . . . . . . . . . . . . . . . 3  
Untrained personnel can perform basic maintenance func-  
tions such as cleaning coils. All other operations should be  
performed by trained service personnel.  
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  
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.  
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  
• 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  
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  
Rigging — Preferred method is with spreader bars from  
above the unit. Use 2-in. (50 mm) OD pipe or hooks in lift-  
ing 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 lift-  
ing 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.  
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . 21  
START-UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . CL-1  
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  
PC 111  
Catalog No. 533-820  
Printed in U.S.A.  
Form 38A-5SI  
Pg 1  
7-94  
Replaces: 38AK-3SI  
Tab 3a  
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 vibra-  
tion 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 (38 in.  
[9.5 mm]) can be moved with finger pressure.  
INSTALLATION  
Fig. 1 — 38AKS Units  
Refrigerant Piping Connections — Line sizes de-  
pend on length of piping required between condensing unit  
and evaporator. See Table 2A or 2B. It is important to con-  
sider 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.  
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
7
are ⁄8-in. (22.2 mm) ODF for inlet and 8-in. (22.2 mm)  
ODM for outlet.  
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.  
Failure to properly install liquid line solenoid at the in-  
door 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 indi-  
cator) field installed. Select the filter drier for maximum unit  
capacity and minimum pressure drop. Figure 5 shows rec-  
ommended locations of filter drier(s) and sight glass. Com-  
plete the refrigerant piping from the evaporator to the con-  
denser 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.  
All panels must be in place when rigging.  
LIFTING  
HOLES  
‘‘A’’  
CENTER OF GRAVITY  
MAX SHIP.  
WT  
‘‘D’’  
mm  
UNIT  
‘‘B’’  
mm  
‘‘C’’  
38AKS  
Lb  
Kg in. mm  
in.  
in. mm in.  
028  
034  
044  
1924  
2115  
872 81 2057 43.0 1092 28.0 711 73.5 1867  
960 81 2057 43.0 1092 28.0 711 73.5 1867  
2797 1207 99 2515 49.0 1245 30.5 775 73.5 1867  
Fig. 2 — Rigging with Spreader Bars  
(Field Supplied)  
3
NOTE: All dimensions are in inches (mm).  
Fig. 3 — Compressor Mounting  
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 gas through  
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 control solenoid used must  
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 recom-  
mendations is to achieve good mixing of the refrigerant leav-  
ing 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.  
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.  
3. Size the suction line from the evaporator through the riser  
for high velocity. Enter the suction pipe sizing charts in  
the Carrier System Design Manual at design tons and equiva-  
lent length (for 2° F [1.1° C] loss). If reading falls be-  
tween 2 sizes on chart, choose the smaller pipe size.  
Fig. 4 — Suction Line Piping to Unit  
with 2 Section Coil Split  
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 compres-  
sor 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.  
TXV  
Thermostatic Expansion Valve  
SAFETY RELIEF — A fusible plug is located on unit liquid  
line before the liquid valve.  
Fig. 5 — Liquid Line Solenoid Valve,  
Filter Drier(s) and Sight Glass Locations  
4
Table 2A — Refrigerant Piping Sizes — 60 Hz  
SINGLE SUCTION RISERS  
LENGTH OF INTERCONNECTING PIPING, FT (M)  
UNIT  
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)  
38AKS  
L
S
L
S
218  
218  
218  
L
S
L
S
S
7
7
7
7
028  
034  
044  
8
8
8
158  
218  
218  
8
8
8
*
8
218  
218  
258  
*
8
218  
218  
258  
*
218  
258  
258  
*
*
*
7
7
7
7
7
8
118  
118  
118  
*
*
L
S
Liquid Line  
Suction Line  
*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.  
DOUBLE SUCTION RISERS — 60 Hz  
LENGTH OF INTERCONNECTING PIPING, FT (M)  
UNIT  
26-50 (7.9-15.2)  
51-75 (15.5-22.8)  
76-100 (23.2.-30.5)  
101-200 (30.8-60.9)  
38AKS  
A
138  
B
158  
C
218  
A
138  
B
158  
C
218  
A
138  
B
158  
C
218  
A
B
C
028  
034  
044  
138  
158  
158  
158  
218  
218  
218  
258  
258  
158  
218  
258  
158  
218  
258  
NOTE: A, B, C dimensions relate to reference diagram.  
Table 2B — Refrigerant Piping Sizes — 50 Hz  
SINGLE SUCTION RISERS  
LENGTH OF INTERCONNECTING PIPING, FT (M)  
26-50 (7.9-15.2) 51-75 (15.5-22.8) 76-100 (23.2-30.5)  
UNIT  
16-25 (4.9-7.6)  
101-200 (30.8-60.9)  
38AKS  
L
S
158  
L
S
218  
218  
218  
L
S
218  
218  
258  
L
S
218  
258  
258  
L
S
7
7
7
7
7
028  
034  
044  
8
8
8
8
8
8
*
*
8
*
8
*
8
218  
258  
258  
*
*
*
7
7
7
7
7
218  
218  
8
*
118  
118  
*
118  
118  
118  
*
*
L
S
Liquid Line  
Suction Line  
*IMPORTANT — Requires a double suction riser, if evaporator is below condensing unit. See table below.  
†For riser, use 158 OD inches.  
NOTE: Liquid and suction line sizes are OD (in.) Equivalent sizes in mm are listed below.  
DOUBLE SUCTION RISERS — 50 Hz  
LENGTH OF INTERCONNECTING PIPING, FT (M)  
UNIT  
26-50 (7.9-15.2)  
51-75 (15.5-22.8)  
76-100 (23.2.-30.5)  
101-200 (30.8-60.9)  
38AKS  
A
B
C
A
B
C
A
B
C
A
B
C
028  
034  
044  
138  
158  
158  
158  
218  
218  
138  
158  
158  
158  
158  
218  
218  
218  
258  
138  
158  
158  
158  
158  
218  
218  
218  
258  
138  
158  
158  
158  
218  
218  
218  
258  
258  
NOTE: A, B, C dimensions relate to reference diagram.  
MAXIMUM LIQUID LIFT  
60 Hz  
50 Hz  
UNIT 38AKS  
Ft  
M
Ft  
M
028  
034  
044  
76  
67  
76  
23  
20  
23  
66  
60  
66  
20  
18  
20  
EQUIVALENT SIZES IN MM  
in.  
mm  
7
8
22.2  
28.6  
34.9  
41.3  
54.0  
66.7  
118  
138  
158  
218  
258  
Unit Size  
Dimension — in. (mm)  
028  
034  
044  
158 (41.3)  
218 (54.0)  
218 (54.0)  
5
closed to prevent an excessive accumulation of refriger-  
ant in the compressor oil.  
3. Power entry is one end only.  
Power Supply — Electrical characteristics of available  
power supply must agree with unit nameplate rating. Supply  
voltage must be within limits shown in Table 3.  
4. Maximum field wire sizes allowed by lugs on terminal  
block are:  
IMPORTANT: Operating unit on improper supply volt-  
age, or with excessive phase imbalance, constitutes abuse  
and may affect Carrier warranty. See Unbalanced 3-Phase  
Supply Voltage, page 7.  
UNIT  
38AKS  
WIRE  
SIZE*  
V-Ph-Hz  
028  
208/230-3-60  
Power Wiring — All power wiring must comply with  
applicable local and national codes. 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. Dis-  
connect(s) must be within sight from and readily accessible  
from unit in compliance with NEC Article 440-14.  
208/230-3-60  
230-3-50  
034  
350 kcmil  
208/230-3-60  
230-3-50  
044  
LEGEND  
AWG  
kcmil  
American Wire Gage  
Thousand Circular Mils  
GENERAL WIRING NOTES  
*All other units use 2/0 AWG (67.4 mm2).  
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.  
5. Terminals for field power supply are suitable for copper,  
copper-clad aluminum, or aluminum conductors. Insula-  
tion must be rated 167 F (75 C) minimum.  
2. The power circuit field supply disconnect should never be  
open except when unit is being serviced or is to be down  
for a prolonged period. When operation is resumed, crank-  
case heater should be energized for 24 hours before start-  
up. If unit is to be shut down for a prolonged period, it  
is recommended that the suction and discharge valves be  
CONDENSER FANS — The fans must rotate counterclock-  
wise when viewed from above. If necessary, correct direc-  
tion of fan rotation by interchanging any 2 power input wires  
at disconnect switch. Affix crankcase heater decal (located  
in installer’s packet) to unit disconnect switch.  
Table 3 — Electrical Data  
60 HZ  
UNIT  
COMPRESSOR  
FAN MOTORS  
UNIT  
38AKS  
Supplied*  
Min. Max.  
Volts  
3 Ph, 60 Hz  
MOCP  
(Fuse)  
MCA  
ICF  
RLA  
LRA  
FLA (ea)  
Qty  
500  
208/230  
380  
187  
342  
414  
518  
254  
418  
508  
632  
124.6  
64.7  
60.7  
52.5  
200  
110  
100  
80  
452.2  
250.9  
226.1  
167.4  
89.8  
45.5  
43.6  
36.5  
446  
247  
223  
164  
6.2  
3.9  
3.1  
3.4  
2
2
2
2
200  
600  
100  
028  
034  
044  
460  
575  
500  
200  
600  
100  
208/230  
380  
187  
342  
414  
518  
254  
418  
508  
632  
145.5  
72.5  
68.7  
54.9  
250  
125  
110  
90  
512.2  
283.9  
256.1  
179.4  
106.5  
52.6  
50.0  
38.5  
506  
280  
253  
176  
6.2  
3.9  
3.1  
3.4  
2
2
2
2
460  
575  
500  
200  
600  
100  
230  
380  
460  
575  
187  
342  
414  
518  
254  
418  
508  
632  
203.0  
111.1  
91.0  
350  
175  
150  
125  
702.4  
389.8  
351.2  
282.8  
147.5  
79.5  
65.4  
57.1  
690  
382  
345  
276  
6.2  
3.9  
3.1  
3.4  
3
3
3
3
81.5  
50 HZ  
UNIT  
COMPRESSOR  
FAN MOTORS  
UNIT  
38AKS  
Supplied*  
Volts  
3 Ph, 50 Hz  
MOCP  
(Fuse)  
MCA  
ICF  
RLA  
LRA  
FLA (ea)  
Qty  
Min.  
Max.  
800  
230  
346  
400  
198  
311  
342  
254  
380  
400  
109.0  
64.9  
60.5  
175  
100  
100  
348.4  
263.4  
226.0  
76.9  
44.9  
43.6  
342  
259  
223  
6.4  
4.4  
3.0  
2
2
2
028  
034  
044  
300  
900  
800  
300  
900  
230  
346  
400  
198  
311  
342  
254  
380  
400  
120.2  
76.1  
68.5  
200  
125  
110  
372.4  
298.4  
256.0  
85.9  
53.9  
50.0  
366  
294  
253  
6.4  
4.4  
3.0  
2
2
2
800  
300  
900  
230  
346  
400  
198  
311  
342  
254  
380  
400  
150.6  
112.6  
90.8  
250  
175  
150  
557.8  
408.8  
351.0  
105.1  
79.5  
65.4  
545  
400  
345  
6.4  
4.4  
3.0  
3
3
3
LEGEND  
*Units are suitable for use on electrical systems where voltage sup-  
plied to unit terminals is not below or above listed minimum and maxi-  
mum limits.  
CSA  
FLA  
ICF  
Canadian Standards Association  
Full Load Amps  
Maximum Instantaneous Current Flow during starting (the point  
in the starting sequence where the sum of the LRA for the start-  
ing compressor, plus the total FLA for all running fan motors is  
maximum).  
LRA  
Locked Rotor Amps  
MCA  
Minimum Circuit Amps (complies with National  
Electrical Code [NEC, U.S.A.], Section 430-24)  
Maximum Overcurrent Protection  
Rated Load Amps  
Underwriters’ Laboratories  
MOCP  
RLA  
UL  
6
FIELD CONNECTIONS  
1. Main Power — Bring wires from the fused disconnect  
switch through hole in bottom rail of unit to control box  
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:  
11  
12  
, and  
(Fig. 6 and 7) and connect terminals  
,
% Voltage Imbalance  
13 line side of terminal block TB1 (see Fig. 8 and 9A  
max voltage deviation from average voltage  
= 100 x  
or 9B). To comply with NEC Article 440-14, the discon-  
nect must be located within sight from and readily ac-  
cessible from unit.  
average voltage  
Example: Supply voltage is 240-3-60.  
2. 24-v Control Power — Units have single point power con-  
nections. Control circuit is directly connected internally  
to unit. Maximum 24-v control circuit is 3 amps.  
AB = 243 v  
BC = 236 v  
AC = 238 v  
NOTE: Wire runs use the following insulated wire:  
INSULATED WIRE SIZE*  
LENGTH  
AWG  
18  
mm2  
0.82  
1.30  
2.08  
0-50  
50-75  
243 + 236 + 238  
Average Voltage =  
16  
3
Over 75  
14  
= 239 volts  
AWG  
American Wire Gage  
*35 C minimum.  
Determine maximum deviation from average voltage:  
(AB) 243 − 239 = 4 v  
(BC) 239 − 236 = 3 v  
(AC) 239 − 238 = 1 v  
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 electri-  
cally interlocked in the control circuit, between thermo-  
Maximum deviation is 4 v. Determine percent voltage  
imbalance:  
2 Y1  
stat TC1 (stage 1, cooling) and terminal  
on TB3.  
4
% Voltage Imbalance = 100 x  
See Fig. 8 for typical field wiring. This is in the 24-v cir-  
cuit. Wires must be run in conduit with ground wire.  
4. Transformer Connections — See unit wiring label dia-  
gram, notes 1 and 2, located behind compressor compart-  
ment end access door.  
239  
= 1.7%  
This amount of phase imbalance is satisfactory as it is be-  
low the maximum allowable 2%.  
IMPORTANT: Ensure power to the crankcase heater  
is always on (except when servicing the unit). If cir-  
cuit breaker inside unit shuts down the compressor, crank-  
case heater remains on.  
IMPORTANT: Contact your local electric utility com-  
pany immediately if the supply voltage phase imbal-  
ance is more than 2%.  
7
LEGEND  
NEC  
VAV  
National Electrical Code  
Variable Air Volume  
NOTES:  
1. There must be minimum (2440 mm) 8 ft. clear air space above  
unit.  
2. The approximate operating weight of the unit is:  
50 AND 60 HZ  
WT  
(Lb)  
WT  
(Kg)  
UNIT  
38AKS028  
38AKS028C  
38AKS034  
38AKS034C  
1650  
1804  
1803  
2009  
748  
818  
818  
911  
3. A ‘‘C’’ in the model number indicates unit has factory-installed  
copper coil.  
Fig. 6 — Dimensional Drawing, 38AKS028,034  
8
LEGEND  
NEC  
National Electrical Code  
NOTES:  
1. There must be minimum (2440 mm) 8 ft. clear air space above  
unit.  
2. The approximate operating weight of the unit is:  
50 HZ AND 60 HZ  
WT  
(Lb)  
WT  
(Kg)  
UNIT  
38AKS044  
2437  
2745  
1106  
1246  
38AKS044C  
3. A ‘‘C’’ in the model number indicates unit has factory-installed  
copper coil.  
Fig. 7 — Dimensional Drawing, 38AKS044  
9
10  
11  
12  
The start-up of the compressor can occur between 3 seconds  
and approximately 5 minutes from the time the control cir-  
cuit is energized due to the anti-short cycle feature of the  
control module (CM).  
START-UP  
Initial Check  
Charge System — Actual start-up should be done only  
under supervision of a qualified refrigeration mechanic. Re-  
fer to charging charts.  
Do not attempt to start the condensing unit, even mo-  
mentarily, until the following steps have been com-  
pleted. Compressor damage may result.  
See Fig. 10-12 for the particular unit being charged. Mea-  
sure pressure at the liquid line service valve, being sure a  
Schrader depressor is used if required. Also, measure liquid  
line temperature as close to the liquid service valve as pos-  
sible. Add or reduce charge until the pressure and tempera-  
ture conditions of the charging charge curve are met. If liq-  
uid 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.  
1. Check all auxiliary components, such as air-handling equip-  
ment, and other equipment. Consult the manufacturer’s  
instructions regarding any other equipment connected  
to the condensing unit. If used, airflow switch must be  
properly installed. See Fig. 8.  
2. Backseat (open) compressor suction and discharge valves.  
Close valves one turn to allow pressure to reach test gages.  
3. Open liquid line service valve.  
4. Set thermostat.  
5. Check tightness of all electrical connections.  
6. Compressor oil level should be visible in sight glass.  
See Service, Oil Charge section on page 19.  
7. Be sure unit is properly leak tested, dehydrated, and charged.  
See below.  
8. Electrical power source must agree with nameplate  
rating.  
Never charge liquid into the low-pressure side of sys-  
tem. Do not overcharge. During charging or removal of  
refrigerant, be sure indoor fan system is operating.  
Operation — Refer to control circuit diagram on the unit,  
or in the unit wiring book.  
Control Module (CM) — The unit control module is  
located in the control section of the control box. See  
Fig. 9A or 9B. It performs several functions. The CM has a  
built-in compressor anti-short-cycle timer which will not al-  
low the compressor to restart until 5 minutes (ϩ90 seconds/  
–75 seconds) have elapsed since the previous shutdown.  
9. Crankcase heater must be firmly locked into compres-  
sor crankcase. Be sure crankcase is warm (heater should  
be on for 24 hours before starting compressor).  
10. Be sure compressor floats freely on the mounting springs.  
See Compressor Mounting section on page 2 and Fig. 3  
for loosening compressor bolts.  
The compressor oil pressure is monitored through the CM.  
The unit is allowed to remain operational as long as the oil  
pressure safety switch (OPS) has not been open for more  
than 2 minutes after the compressor has started. If after start-  
up, the OPS is open for more than 2 minutes, the CM shuts  
down the compressor and places the unit in a lockout con-  
dition. The CM activates the fault indication circuit, and the  
field-supplied unit service lamp is illuminated (if so equipped).  
The unit cannot be restarted until power is interrupted at the  
unit, resetting the CM. The 5-minute recycle time relay is  
initiated.  
The CM also monitors the high-pressure switch (HPS) and  
compressor thermal protection. If at any time the HPS opens,  
the CM shuts down the compressor and places the unit in a  
lockout condition. The CM activates the fault indication cir-  
cuit, and the field-supplied unit service lamp is illuminated  
(if so equipped). The unit cannot be restarted until the HPS  
is reset and until power is interrupted at the unit, resetting  
the CM. The 5-minute recycle time relay is initiated.  
Leak Test and Dehydration — Leak test the entire  
refrigerant system by the pressure method described in the  
Carrier Training Booklet; GTAC II, Module 4 - System  
Dehydration.  
Preliminary Charge — Refer to Carrier Training Book-  
let; GTAC II, Module 5 for charging methods and proce-  
dures. Charge system with approximately 25 lbs (11.3 kg) of  
R-22 by the liquid charging method (charging through liq-  
uid service valve), on the high side, and charging by weight.  
Charge per Fig. 10-12.  
Start Unit — Close field disconnect. Set thermostat above  
ambient temperature so that there is no demand for cooling.  
Now, only the crankcase heater is energized. After the heater  
has been on for 24 hours, the unit can be started. If no time  
has elapsed since the preliminary charge step has been com-  
pleted, it is unnecessary to wait the 24-hour period.  
Close the compressor circuit breaker, then reset the in-  
door thermostat below ambient temperature, so that a call  
for cooling is ensured.  
If the unit shuts down on an automatic reset switch, such  
as the low-pressure switch (LPS), the compressor will be al-  
lowed to restart when the switch recloses and the CM anti-  
short-cycle time has elapsed.  
NOTE: Do not use the compressor circuit breaker to start  
and stop compressor, except in an emergency.  
13  
14  
15  
16  
FOR SERVICING ONLY — To speed up the 5-minute anti-  
short cycle, a temporary jumper may be placed between ter-  
minals T1 and T6 of the control module.  
Complete Unit Stoppage  
CAUSES — Interruption of supplied power, compressor over-  
temperature protection, or open HPS causes compressor  
stoppage.  
RESTART — The unit recycles and restarts automatically  
under the CM when power is restored. Stoppage by HPS, or  
compressor circuit breaker requires manual resetting of the  
control circuit. To restart the CM timer when HPS is tripped,  
it is necessary to interrupt power to the unit, restarting the  
CM logic. It is necessary to manually reset the compressor  
circuit breaker at the unit.  
If LPS is not closed within 2 minutes after compressor  
starts, the compressor locks out and the outdoor fans con-  
tinue to run. It stays locked out for 5 minutes until the CM  
anti-short cycle timer expires. After 5 minutes, the LPS is  
bypassed by the BPR (winter start control). It remains jum-  
pered for 2 minutes. Because the LPS is jumpered, the com-  
pressor restarts and runs for the 2-minute time period. At  
the end of this 2 minutes, if the LPS has still not closed, the  
compressor is again locked out. The outdoor fans continue  
to run as long as there is a call for cooling. Automatic reset  
of the LPS causes the CM to recycle so that the compressor  
can start.  
This jumper must be removed after servicing is com-  
plete. Failure to remove this jumper is considered abu-  
sive treatment and will void the Carrier warranty.  
Bypass Relay (BPR) — All units are equipped with a  
BPR located in the control section of the control box. See  
Fig. 9Aor 9B. The function of the BPR is to provide a 2-minute  
bypass of the LPS at start-up, and to energize the unload-  
er(s) at start-up to provide unloaded compressor starting. Two  
minutes after the compressor starts, the BPR completes its  
function and is no longer active in the control circuit until  
the next restart of the unit.  
Time-Delay Relay (TDR) (50 Hz Only) — This solid-  
state delay-on-make relay is factory set for a 1-second delay.  
The number 1 dip switch is set to the ON position, and all  
the other dip switches are set to the OFF position. Once the  
control relay (CR) is energized, the compressor contactor C1  
is powered, and the first set of compressor windings is en-  
ergized. After the 1-second time delay, contactor C1A is pow-  
ered and the second set of compressor windings is energized  
(part-wind start).  
If sufficient compressor oil pressure has not been built within  
2 minutes after the compressor starts, the unit is completely  
deenergized until the oil pressure switch is manually reset at  
the unit.  
Sequence of Operation — When space thermostat  
calls for cooling, the no. 1 condenser fan and compressor  
start after CM initial time delay of 3 (ϩ2/–1) seconds. If an  
optional airflow switch is used, compressor and no. 1 con-  
denser fan will not start until sufficient indoor airflow has  
closed the switch. After 3 seconds the compressor starts and  
the liquid line solenoid valve for solenoid drop control opens.  
The crankcase heater is deenergized. If the head pressure reaches  
260 psig (1792 kPa) the second condenser fan starts. Fan  
no. 3 (38AKS044 only) starts if outdoor ambient air rises  
above 80 F (26.7 C).  
If unit or circuit stoppage occurs more than once due to  
any safety device, the trouble should be corrected be-  
fore any attempt to restart.  
SERVICE  
If cooling demand is low, suction pressure at the com-  
pressor drops. As the pressure drops, the compressor un-  
loads 2 banks of cylinders as required. If cooling demand is  
high and 2-stage operation is used, the second stage of the  
thermostat activates the capacity control liquid line solenoid  
which activates the second stage evaporator coil. The com-  
pressor cylinders load or unload in response to compressor  
suction pressure to meet evaporator load.  
Two minutes after compressor starts, the BPR timer is deen-  
ergized and the LPS bypass is deactivated. If the LPS trips  
during the first 2 minutes of operation, the compressor will  
remain operational. If the LPS trips after 2 minutes, the com-  
pressor operation is interrupted, and the compressor cannot  
restart until the 5-minute CM anti-short cycle timer expires.  
As the space cooling load is satisfied, the second stage of  
the thermostat opens, and closes the field-supplied capacity  
control liquid line solenoid valve to deactivate the second  
stage coil. The compressor adjusts the number of active cyl-  
inders to meet the new load. When the space temperature is  
satisfied, the first stage of the thermostat opens and the con-  
trol relay and the BPR open. This closes the solenoid drop  
control valve. The compressor stops and the crankcase heater  
is energized, preventing refrigerant from migrating to the com-  
pressor during the off cycle (solenoid drop refrigerant con-  
trol). The CM anti-short cycling timer is energized and runs  
for approximately 5 minutes. During this time, the compres-  
sor is not able to restart.  
Turn off all power to unit before proceeding.  
Access for Servicing (See Fig. 13)  
COMPRESSOR SECTION — The compressor compart-  
ment has 2 side access panels and one front door for ser-  
vicing, providing access to compressor, all components of  
the refrigerant system, electrical controls, and control box.  
After opening front door there is an inner cover that must be  
removed for access to control box (except 208/230-v and  
460-v units).  
OIL PRESSURE SAFETY SWITCH — Switch is manually  
reset, and accessed by removing the side access panel on the  
left side of the unit (as viewed from the compressor end).  
See Fig. 13. The OPS is found in the compressor junction  
box. Open the compressor circuit breaker prior to removing  
the compressor junction box cover in order to access the OPS.  
The liquid line service valve can be found behind the side  
access door on the right side of the unit (as viewed from the  
compressor end).  
CONDENSER SECTION — Condenser fan motors and fans  
can be serviced by removal of outlet grilles or side panels.  
If a fan motor is serviced, be sure the wire fan guard is in  
place over each fan before starting unit. See Fig. 14 for proper  
fan adjustment. Tighten fan hub securely on motor shaft with  
setscrew which bears against the key. Be sure to replace Per-  
magum and rubber cap over end of motor shaft to protect  
against moisture causing fan to rust on shaft.  
17  
TRAN1  
CM  
CR1  
FC3  
FC2  
FC  
C1  
CB2  
CB1  
TRA2  
TB3  
TB2  
COMPRESSOR END AND RIGHT-SIDE VIEW  
COMPRESSOR END, CONTROL PANEL REMOVED  
LIQUID LINE  
SERVICE  
VALVE  
COMPRESSOR END, RIGHT-SIDE ACCESS DOOR  
OIL PRESSURE SAFETY SWITCH  
COMPRESSOR END, LEFT-SIDE ACCESS DOOR  
(JUNCTION BOX COVER REMOVED)  
Fig. 13 — 38AKS Unit with Access Panels Removed  
18  
Fan Adjustment — Adjust fan as shown in Fig. 14.  
Capacity Control — Capacity control is by 2 suction  
pressure actuated unloaders. Each controls 2 cylinders. Un-  
loaders are factory set (see Table 1A or 1B) but may be field  
adjusted. Number 1 unloader is on cylinder bank on same  
side of compressor as terminal box.  
CONTROL SET POINT — The control set point (cylinder  
load point) is adjustable from 0 to 85 psig (0 to 586 kPag).  
To adjust, turn control set point adjustment nut (Fig. 15) clock-  
wise to its bottom stop. In this position, set point is  
85 psig (586 kPag). Then, turn adjustment counterclockwise  
to desired control set point. Every full turn counterclock-  
wise decreases set point by 7.5 psig (52 kPag).  
NOTE: Dimension in ( ) is in millimeters.  
Fig. 14 — Location of Prop on Motor Shaft from  
Outside of Orifice Ring  
Oil Charge — Compressors are factory charged with oil  
as follows:  
AMOUNT  
COMPRESSOR  
pints (liters)  
06E9265  
06E9275  
06E9299  
20.0 (9.4)  
20.0 (9.4)  
19.0 (9.0)  
When additional oil or a complete charge is required, use  
only Carrier-approved compressor oil:  
Petroleum Specialities Inc. . . . . . . . . . . . . . . . . . .Cryol 150  
Texaco, Inc. . . . . . . . . . . . . . . . . . . . . . . . . .Capella WF-32  
Witco Chemical Corp. . . . . . . . . . . . . . . . . . . .Suniso 3 GS  
IMPORTANT: Do not use drained oil or use oil that  
has been exposed to atmosphere. Refer to Carrier Train-  
ing Booklet, GTAC II, Module 5, for procedures to  
add oil. To remove oil, isolate the compressor, reclaim  
internal compressor charge, and use the compressor drain  
plug.  
Fig. 15 — Capacity Control Valve  
PRESSURE DIFFERENTIAL — The pressure differential  
(difference between cylinder load and unload points) is ad-  
justable from 6 to 22 psig (41 to 152 kPag). To adjust, turn  
pressure differential adjustment screw (Fig. 15) counter-  
clockwise to its backstop position. In this position, differ-  
ential is 6 psig (41 kPag). Then, turn adjustment clockwise  
to desired pressure differential. Every full turn clockwise in-  
creases differential by 1.5 psig (10 kPag).  
Liquid Shutoff/Charging Valve — Valve is located  
inside the compressor compartment and is provided with  
1
4-in. flare connection for field charging.  
19  
Oil Pressure Safety Switch (OPS) — The OPS in  
the control circuit stops the compressor and unit, if proper  
oil pressure differential is not established at start-up or main-  
tained during operation. If OPS stops the unit, determine the  
cause and correct before restarting unit. Failure to do so will  
constitute abuse. Equipment failure due to abuse may void  
the warranty.  
Head Pressure Control — Control maintains ad-  
equate discharge pressure under low ambient temperature con-  
ditions. See Table 5.  
FAN CYCLING — These 38AKS units have standard pro-  
vision for fully automatic intermediate-season head pressure  
control through condenser fan cycling. Fan no. 2 is cycled  
by a fan cycling pressure switch (FCPS) which responds to  
variation in discharge pressure. The pressure sensor is lo-  
cated in the liquid line of the refrigerant circuit. Fan no. 3  
cycling is controlled by outdoor-air temperature through an  
air temperature switch (ATS) (38AKS044 units only).  
Compressor Protection  
CIRCUIT BREAKER — Calibrated trip manual reset, am-  
bient compensated, magnetic breaker protects against motor  
overload and locked rotor conditions.  
CONTROL MODULE TIMER — This control protects com-  
pressor against short cycling. See Sequence of Operation on  
page 17.  
Table 5 — Minimum Outdoor-Air  
Operating Temperature  
CRANKCASE HEATER — This minimizes absorption of  
liquid refrigerant by oil in crankcase during brief or ex-  
tended shutdown periods.  
MIN OUTDOOR TEMP, F (C)  
COND  
UNIT  
COMPR  
Low Ambient  
Control  
TEMP,  
F (C)  
Standard  
Unit  
38AKS CAP. (%)  
(Motormaster)  
100  
90 (32)  
80 (27)  
70 (21)  
31 (–1)  
35 (2)  
43 (6)  
–20 (–29)  
–20 (–29)  
–20 (–29)  
IMPORTANT: Never open any switch or disconnect  
that deenergizes the crankcase heater unless unit is be-  
ing serviced or is to be shut down for a prolonged pe-  
riod. After a prolonged shutdown on a service job, en-  
ergize the crankcase heater for 24 hours before starting  
the compressor.  
028  
034  
044  
67  
33  
100  
67  
33  
90 (32)  
80 (27)  
70 (21)  
30 (–1)  
34 (1)  
42 (6)  
–20 (–29)  
–20 (–29)  
–20 (–29)  
100  
67  
33  
90 (32)  
80 (27)  
70 (21)  
25 (–4)  
30 (–1)  
35 (2)  
–20 (–29)  
–20 (–29)  
–20 (–29)  
High-Pressure Switch — This switch has fixed, non-  
adjustable settings. Switch is mounted on the compressor (See  
Table 4).  
The ATS is located in the lower divider panel between the  
compressor compartment and condenser section. Through a  
hole in the panel, the sensing element is exposed to air en-  
tering the no. 1 fan compartment. Fan no. 1 is noncycling.  
Table 6 shows the operating settings of the FCPS and the  
ATS.  
Low-Pressure Switch — This switch has fixed, non-  
adjustable settings. Switch is mounted on the compressor.  
(See Table 4.)  
Table 4 — Pressure Switch Settings, psig (kPa)  
Table 6 — Fan Cycling Controls  
HIGH PRESSURE  
LOW PRESSURE  
CONTROL BY  
Temp, F (C)  
SWITCH OPENS  
SWITCH CLOSES  
Cutout  
Cut-in  
Cutout  
Cut-in  
70 ± 3 (21 ± 1.7)  
80 ± 3 (27 ± 1.7)  
426 ± 7  
(2937 ± 48)  
320 ± 20  
(2206 ± 138)  
27 ± 3  
(186 ± 21)  
44 ± 5  
(303 ± 34)  
Pressure,  
psig (kPa)  
160 ± 10 (1103 ± 69) 260 ± 15 (1793 ± 103)  
Winter Start Control — Bypass relay timer bypasses  
low-pressure switch for 2 minutes on unit start-up.  
NOTE: See Fig. 6 and 7 for fan arrangement.  
20  
TROUBLESHOOTING  
PROBABLE REMEDY  
SYMPTOM AND PROBABLE CAUSE  
COMPRESSOR DOES NOT RUN  
1. Control circuit breaker tripped  
2. Power line open  
1. Reset control circuit breaker  
2. Reset circuit breaker  
3. Oil pressure switch tripped  
4. Safety device tripped  
5. Contactor stuck open  
6. Loose terminal connection  
7. Improperly wired controls  
8. Seized compressor  
3. Reset oil pressure switch at unit  
4. Reset control circuit with thermostat  
5. Replace contactor  
6. Check connections  
7. Check and rewire  
8. Check motor winding for open or short.  
Replace compressor, if necessary  
9. Check line voltage — determine location of  
voltage drop and remedy deficiency  
10. Check motor winding for open or short.  
Replace compressor, if necessary  
9. Low line voltage  
10. Compressor motor defective  
COMPRESSOR STOPS ON LOW-PRESSURE  
CONTROL  
1. Compressor suction shutoff valve partially closed  
2. Low refrigerant charge  
1. Open valve  
2. Add refrigerant  
3. Liquid line solenoid valve(s) fails to open  
3. Check liquid line solenoid valve for proper  
operation. Replace if necessary  
4. Open valve  
4. Liquid line shutoff valve closed  
COMPRESSOR STOPS ON HIGH-PRESSURE  
CONTROL  
1. Compressor discharge valve partially closed  
2. Air in system  
1. Open valve or replace if defective  
2. Purge and evacuate system  
3. Check motor wiring and repair or replace if  
defective  
3. Condenser fan(s) not operating  
4. System is overcharged.  
4. Reclaim charge as needed  
UNIT OPERATES TOO LONG OR  
CONTINUOUSLY  
1. Low refrigerant charge  
1. Add refrigerant  
2. Control contacts fused  
2. Replace control  
3. Air in system  
4. Partially plugged expansion valve or filter drier  
3. Purge and evacuate system  
4. Clean or replace  
SYSTEM IS NOISY  
1. Piping vibration  
2. Compressor noisy  
1. Support piping as required  
2. Check valve plates for valve noise. Replace  
compressor if bearings are worn  
COMPRESSOR LOSES OIL  
1. Leak in system  
1. Repair leak  
2. Crankcase heaters not energized during  
shutdown  
2. Check wiring and relays. Check heater and  
replace if defective  
3. Improper interconnecting piping design  
3. Check piping for oil return. Replace if  
necessary  
FROSTED SUCTION LINE  
1. Expansion valve admitting excess refrigerant  
1. Adjust expansion valve  
HOT LIQUID LINE  
1. Shortage of refrigerant due to leak.  
2. Expansion valve opens too wide  
1. Repair leak and recharge  
2. Adjust expansion valve  
FROSTED LIQUID LINE  
1. Restricted filter drier  
1. Remove restriction or replace  
COMPRESSOR WILL NOT UNLOAD  
1. Defective unloader  
1. Replace  
2. Defective capacity control solenoid valve  
3. Miswired liquid line solenoid  
2. Replace valve  
3. Rewire correctly  
4. Replace spring  
4. Weak, broken, or wrong valve body spring  
COMPRESSOR WILL NOT LOAD  
1. Miswired capacity control liquid solenoid  
2. Defective capacity control solenoid valve  
3. Plugged strainer (high side)  
4. Stuck or damaged unloader piston or piston  
ring(s)  
1. Rewire correctly  
2. Replace valve  
3. Clean or replace strainer  
4. Clean or replace the necessary parts  
21  
PACKAGED SERVICE TRAINING  
Our packaged service training programs provide an excellent way to increase your knowledge of the  
equipment discussed in this manual. Product programs cover:  
• Unit Familiarization  
• Installation Overview  
• Maintenance  
• Operating Sequence  
A large selection of product, theory, and skills programs is available. All programs include a video  
cassette and/or slides and a companion booklet. Use these for self teaching or to conduct full training  
sessions.  
For a free Service Training Material Catalog (STM), call 1-800-962-9212. Ordering instructions are  
included.  
Copyright 1994 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. 533-820  
Printed in U.S.A.  
Form 38A-5SI  
Pg 22  
7-94  
Replaces: 38AK-3SI  
Tab 3a  
START-UP CHECKLIST  
(Remove and store in job file)  
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?  
IF SO, WHERE:  
(Y/N)  
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?  
ARE THE POWER WIRES TO THE UNIT SIZED AND INSTALLED PROPERLY?  
(Y/N)  
(Y/N)  
HAVE COMPRESSOR HOLDDOWN BOLTS BEEN LOOSENED?  
(Y/N)  
CONTROLS  
ARE THERMOSTAT AND INDOOR FAN CONTROL WIRING  
CONNECTIONS MADE AND CHECKED?  
(Y/N)  
ARE ALL WIRING TERMINALS (including main power supply) TIGHT?  
HAS CRANKCASE HEATER BEEN ENERGIZED FOR 24 HOURS?  
(Y/N)  
(Y/N)  
INDOOR UNIT  
HAS WATER BEEN PLACED IN DRAIN PAN TO CONFIRM PROPER DRAINAGE?  
ARE PROPER AIR FILTERS IN PLACE? (Y/N)  
HAVE FAN AND MOTOR PULLEYS BEEN CHECKED FOR PROPER ALIGNMENT?  
(Y/N)  
(Y/N)  
DO THE FAN BELTS HAVE PROPER TENSION?  
(Y/N)  
PIPING  
ARE LIQUID LINE SOLENOID VALVE(S) LOCATED AT THE EVAPORATOR COIL AS REQUIRED?  
(Y/N)  
HAVE LEAK CHECKS BEEN MADE AT COMPRESSOR, CONDENSER, EVAPORATOR,  
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)?  
(Y/N)  
1
ARE THE COMPRESSOR OIL SIGHT GLASSES SHOWING ABOUT 2 FULL?  
(Y/N)  
CHECK VOLTAGE IMBALANCE  
LINE-TO-LINE VOLTS:  
(AB + AC + BC)/3 = AVERAGE VOLTAGE =  
MAXIMUM DEVIATION FROM AVERAGE VOLTAGE =  
AB  
V
AC  
V
BC  
V
V
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  
C. Start-Up  
CHECK EVAPORATOR FAN SPEED AND RECORD.  
CHECK CONDENSER FAN SPEED AND RECORD.  
AFTER AT LEAST 10 MINUTES RUNNING TIME, RECORD THE FOLLOWING MEASUREMENTS:  
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  
1
1
OIL LEVEL AT 8 TO ⁄3 FULL?  
(Y/N)  
NOTES:  
Copyright 1994 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. 533-820  
Printed in U.S.A.  
Form 38A-5SI  
Pg CL-2  
7-94  
Replaces: 38AK-3SI  
Tab 3a  

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