COMPRESSOR WILL NOT START - TM-5-4120-352-140038

TM 5-4120-352-14

Table 4-2. Troubleshooting (Cont)

Malfunction

Test or Inspection

Corrective Action

3. EVAPORATOR OR CONDENSER FAN FAILS TO OPERATE (CONT)

Step 7. Check to see if evaporator fan or condenser fan is defective or binding.

Relieve binding or replace fan (para 4-43).

Step 8. Check to see if condenser fan high-low thermostatic switch is defective.

Replace defective thermostatic switch (para 4-41).

Step 9. Test condenser fan relay for defective operation.

Replace defective relay (para 4-43).

Step 10. Test evaporator fan motor and condenser fan motor for defective operation.

Replace defective fan motor (para 4-38 and 4-40).

4. COMPRESSOR WILL NOT START

Step 1. Check to see if compressor or control circuit breakers or selector switch is improperly set.

Reset controls properly.

Step 2. Check for defective or tripped compressor internal temperature overload switch.

Allow unit to COOL If condition continues, report deficiency to direct support maintenance.

Step 3. Check for loose electrical connections or faulty wiring.

Tighten loose connections. Repair faulty wiring.

Step 4. Test for open control circuit by means of continuity check (para 4-12).

Report open-circuit condition to direct support maintenance.

Step 5. Check to see if contacts on high or low pressure cutout switch are open.

Reset pressure switches. If condition continues, report deficiency to direct support maintenance.

Step 6. Test control circuit breaker and compressor circuit breaker for faulty operation.

Replace defective circuit breaker (para 4-44 thru 4-48 or 4-50 thru 4-54).

Step 7. Test control transformer and rectifier for defective operation.

Replace defective transformer (para 4-45 and defective rectifier (para 4-46).

Step 8. Test for defective time delay relay.

Replace defective relay (para 4-43).

Step 9. Test for defective compressor relay.

Replace defective relay (para 4-43).

Step 10. Check to see if compressor motor is defective.

Report motor-fault condition to direct field maintenance.

5. COMPRESSOR STARTS BUT CUTS OUT ON OVERLOAD

Step 1. Check to see if evaporator fan speed switch is set at LOW speed.

Reset switch to HIGH speed.

Step 2. Check for defective or tripped compressor internal temperature overload switch.

Allow unit to COOL If condition continues, report deficiency to direct support maintenance.

Step 3. Check for high pressure due to improper condenser coil airflow.

Clean condenser coil and louvers. Verify proper operation of condenser fan.

Step 4. Check for improperly adjusted or defective refrigerant control valves.

Report condition to direct support maintenance.

Step 5. Test condenser fan for motor failure.

Replace defective motor (para 4-38 and 4-40).

4-4