Refrigeration Trouble Shooting Guide
Always use a certified trained Refrigeration Technician when repair of your refrigeration system is required.
Malfunction | Possible Cause | Solution |
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Compressor will not start - no hum | Service cord unplugged | Plug in service cord |
| Fuse blown or removed | Replace fuse |
| Overload tripped | Determine reasons and correct |
| Control stuck open | Repair or replace |
| Wiring incorrect | Check wiring against diagram |
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Compressor will not start - hums but | Improperly wired | Check wiring against the diagram |
trips on overload protector | Low voltage to unit | Determine reason and correct |
| Staring capacitor defective | Determine reason and replace |
| Relay failing to close | Determine reason, correct or replace |
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Compressor starts & runs, but short | Low voltage to unit | Determine reason and correct |
cycles on overload protector | Overload defective | Check current, replace overload protector |
| Excessive head pressure | Check ventilation or restriction in system |
| Compressor very | Check refrigerant charge, fix leak if req ‘d |
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Compressor operates long or continuously | Short of refrigerant | Fix leak, add charge |
| Control contact stuck | Repair or replace |
| Evaporator coil iced | Determine cause, defrost manually |
| Restriction in refrigeration system | Determine location & remove |
| Dirty condenser | Clean condenser |
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Compressor runs fine, but short cycles | Overload protector | Check wiring diagram |
| Cold control | Differential too |
| Overcharge | Reduce charge |
| Air in system | Recover and recharge |
| Undercharge | Fix leak, add refrigerant |
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Starting capacitor open, shorted or blown | Relay contacts stuck | Clean contacts or replace relay |
| Low voltage to unit | Determine reason and correct |
| Improper relay | Replace |
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Relay defective or burned out | Incorrect relay | Check and replace |
| Voltage too high or low | Determine reason and correct |
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Refrigerated space too warm | Control setting too high | Reset control |
| Refrigerant overcharge | Recover refrigerant |
| Dirty condenser | Clean condenser |
| Evaporator coil iced | Determine reason and defrost |
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Standard temperature system freezes | Control setting is too low | Reset the control |
the product | Control points stuck | Replace the control |
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Objectionable noise | Fan blade hitting shroud | Reform/cut away small section of shroud |
| Tube raffle | Locate and reform |
| Vibrating fan blade | Replace fan blade |
| Condenser fan motor raffles | Check motor bracket mounting, tighten |
| General vibration | Compressor suspension bolts too tight |
| Worn fan motor bearings | Replace fan motor |
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