Carrier 38AH024-034 User Manual
Page 22
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TROUBLESHOOTING (cont)
PROBLEM
SOLUTION
COMPRESSOR CYCLES ON LOW-PRESSURE
SWITCH (cont)
Airflow Restricted
1. Coil iced up.
1. Check refrigerant charge.
2. Coil dirty.
2. Clean coil fins.
3. Air filters dirty.
3. Clean or replace filters.
4. Dampers closed.
4. Check damper operation and position.
Indoor-Air Fan Stopped
1. Electrical connections loose.
1. Tighten all connections.
2. Fan relay defective.
2. Replace relay.
3. Motor overload open.
3. Power supply.
4. Motor defective.
4. Replace motor.
5. Fan belt broken or slipping.
5. Replace or tighten belt.
COMPRESSOR STOPS ON OIL PRESSURE
SWITCH
1. Oil level too low or too high.
1. Check oil level requirements; adjust oil level until within
2. Compressor is short cycling.
view of sight glass when running.
2. Check for
3. Crankcase heater off.
a. Thermostat location and operation.
b. Safety device lockout circuit operation.
c. Low-pressure switch operation.
3. Check relay operation; replace crankcase heater(s), if
4. Low refrigerant charge.
defective.
4. Adjust charge as required.
5. Refrigerant floodback.
5. Adjust TXV superheat.
6. Evaporator coil is blocked or iced.
6. Check and correct as required.
7. Evaporator fan not operating.
7. Check and correct as required.
8. Distributor and/or TXV too large.
8. Check sizing at design conditions; change if incorrect for
9. Suction riser too large.
current application.
9. Check line sizing at minimum design condition; change
10. Defective oil pressure switch.
piping if incorrect.
10. Check switch for proper operation; check capillary lines for
11. Plugged oil pump inlet screen.
plugged lines.
11. Clean oil pump screen.
12. Faulty oil pump drive segment.
12. Replace drive segment.
13. Worn oil pump.
13. Replace bearing head assembly.
14. Worn compressor bearings.
14. Replace compressor; see 06D service instructions.
COMPRESSOR RUNNING BUT COOLING
INSUFFICIENT
Suction Pressure Low
1. Refrigerant charge low.
1. Add refrigerant.
2. Head pressure low.
2. Check refrigerant charge.
3. Air filters dirty.
Check outdoor-air fan thermostat settings.
3. Clean or replace filters.
4. Expansion valve power head defective.
4. Replace power head.
5. Indoor coil partially iced.
5. Check low-pressure setting.
6. Indoor airflow restricted.
6. Remove obstruction.
Suction Pressure High
1. Unloaders not functioning.
1. Check unloader adjustments.
2. Compressor valve defective.
Check unloader setting.
2. See 06D compressor service literature.
3. Heat load excessive.
3. Check for open doors or windows in vicinity of fan coil
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