Troubleshooting Checklist for Refrigeration Systems (Continued)
Compressor will not run.
Repair or replace compressor.
Cut-in point of low-pressure control
Set L.P. control switch to cut-in at
switch too high.
High-pressure control switch does not
Check discharge pressure and reset
H.P. control switch.
1. Defective switch.
1. Repair or replace switch.
2. Electric power cut off.
2. Check power supply.
3. Service or disconnect switch open.
4. Fuses blown.
3. Close switches.
4. Test fuses and renew if necessary.
5. Overload relays tripped.
5. Reset relays and find cause of
6. Low voltage.
6. Check voltage (should be within 10
7. Electrical motor in trouble.
percent of nameplate rating).
8. Trouble in starting switch or control
7. Repair or replace motor.
9. Compressor motor stopped by
oil-pressure differential switch.
8. Close switch manually to test
power supply. If OK check control
circuit including temperature and
9. Check oil levels in crankcase. Check
Sudden loss of oil from
Liquid refrigerant slugging back to
Adjust or replace expansion valve.