TM 9-4120-399-14
Table 5-1. Direct Support Troubleshooting. (Continued).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
DISCHARGE PRESSURE TOO HIGH. (Continued).
1.
Step 2. Check for refrigerant overcharge.
See paragraph 5-13.
Step 3. Check sight glass for air in refrigerant system.
Leak check per paragraph 5-10.
Step 4. Check operation of condenser fan motor.
Replace defective fan motor per para. 4-45.
Step 5. Check to see if condenser fan is loose on shaft.
Tighten condenser fan on shaft per para. 4-45.
Step 6. Check to see if there is too much oil in the refrigerant system.
Remove compressor and check oil level per para. 5-28.
DISCHARGE PRESSURE TOO LOW.
2.
Step 1. Check too see that cold outside air is not entering the room.
Step 2. Check sight glass for low refrigerant charge.
Charge the refrigerant system per paragraph 5-12.
Step 3. Check pressure regulating valve.
Replace pressure regulating valve per para. 5-20.
Step 4. Check compressor operation.
Replace defective compressor per para. 5-28.
5-2
