Carrier 38AH024-034 - Manual (Page 21)

TROUBLESHOOTING
PROBLEM SOLUTION
COMPRESSOR DOES NOT RUN
Contactor Open
1. Power off. 1. Restore power.
2. Fuses blown in field power circuit. 2. After finding cause and correcting, replace with correct size
fuse.
3. No control power.
4. Thermostat circuit open.
5. Time Guard® II device not operating.
6. Compressor circuit breaker tripped.
3. Check secondary fuse(s); replace with correct type and size.
Replace transformer if primary windings receiving power.
4. Check thermostat setting.
5. Check Time Guard 11 devices.
6. Check for excessive compressor current draw. Reset breaker;
replace if defective.
7. Reset lock-out circuit at thermostat or circuit breaker.
8. See oil pressure switch section.
9. Check for refrigerant undercharge, obstruction of indoor air- 7. Safety device lock-out circuit active.
8. Oil pressure switch tripped.
9. See oil pressure switch section.
flow, or whether compressor suction shutoff valve is fully open.
Make sure liquid line solenoid valve(s) is open.
10. High-pressure switch open. 10. Check for refrigerant overcharge, obstruction of outdoor air-
flow, air in system, or whether compressor discharge valve is
fully open. Be sure outdoor fans are operating correctly.
11. Compressor overtemperature switch open. 11. Check for open condition. Allow for reset. Replace if defective.
12. Loose electrical connections. 12. Tighten all connections.
13. Compressor stuck.
Contactor Closed
13. See 06D compressor service literature.
1. Compressor leads loose. 1. Check connections.
2. Motor windings open.
3. Single phasing. 2. See 06D compressor service literature.
3. Check for blown fuse. Check for loose connection at compres-
sor terminal.
COMPRESSOR STOPS ON HIGH-PRESSURE
SWITCH
Outdoor Fan On
1. High-pressure switch faulty. 1. Replace switch.
2. Reversed fan rotation. 2. Confirm rotation, correct if necessary.
3. Airflow restricted. 3. Remove obstruction.
4. Air recirculating. 4. Clear airflow area.
5. Noncondensables in system.
6. Refrigerant overcharge.
7. Line voltage incorrect.
8. Refrigerant system restrictions. 5. Purge and recharge as required.
6. Purge as required.
7. Consult power company.
8. Check or replace filter drier, expansion valve, etc. Check that
compressor discharge service valve is fully open.
Outdoor Fan Off
1. Fan slips on shaft. 1. Tighten fan hub setscrews.
2. Motor not running. 2. Check power and capacitor.
3. Motor bearings stuck. 3. Replace bearings.
4. Motor overload open. 4. Check overload rating. Check for fan blade obstruction.
5. Motor burned out. 5. Replace motor.
COMPRESSOR CYCLES ON LOW-PRESSURE
SWITCH
Indoor-Air Fan Running
1. Compressor suction service valve partially 1. Open valve fully.
closed.
2. Liquid line solenoid valve(s) fails to open. 2. Check liquid line solenoid valve(s) for proper operation.
Replace if necessary.
3. Filter drier plugged. 3. Replace filter drier.
4. Expansion valve power head defective. 4. Replace power head.
5. Low refrigerant charge. 5. Add charge. Check low-pressure switch setting.
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