TROUBLESHOOTING & SERVICING REFRIGERATION SYSTEM
| PROBLEM |
| POSSIBLE CAUSE |
| REMEDY |
1. | Condensing unit fails to start - no | 1. | Line disconnect switch open. | 1. | Close start or disconnect switch. |
| hum. | 2. | Fuse removed or blown. | 2. | Replace fuse. |
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| 3. | Overload protector tripped. | 3. | Determine reason and |
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| 4. | Control stuck in open position. |
| correct/replace control. |
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| 4. | Repair or replace control. | ||
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| 5. | Wiring improper or loose. | 5. | Check wiring against diagram. |
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2. | Compressor fails to start - | 1. | Improperly wired. | 1. | Check wiring against diagram. |
| hums and trips on overload | 2. | Low voltage to unit. | 2. | Determine reason and correct. |
| protector. | 3. | Starting capacitor defective. | 3. | Determine reason and replace. |
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| 4. | Relay failing to close. | 4. | Determine reason and |
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| 5. | Compressor motor has a winding |
| correct/replace if necessary. |
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| 5. | Replace compressor. | ||
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| open or shorted. | 6. | Replace compressor. |
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| 6. | Internal mechanical trouble in | ||
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| compressor. |
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3. | Compressor starts, but fails | 1. | Improperly wired. | 1. | Check wiring against diagram. |
| to switch off of “start” winding. | 2. | Low voltage to unit. | 2. | Determine reason and correct. |
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| 3. | Relay failing to open. | 3. | Determine reason and |
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| 4. | Run capacitor defective. |
| correct/replace if necessary. |
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| 4. | Determine reason and replace. | ||
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| 5. | Excessively high discharge | 5. | Check discharge |
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| pressure. |
| possible overcharge, or |
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| 6. | Compressor motor has a winding |
| insufficient cooling on condenser. |
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| 6. | Replace compressor. | ||
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| open or shorted. |
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| 7. | Internal mechanical trouble in | 7. | Replace compressor. |
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| compressor. |
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4. | Compressor starts and runs, | 1. | Additional current passing through | 1. | Check wiring diagram. |
| but short cycles on overload |
| overload protector. |
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| protector. | 2. | Low voltage to unit (or | 2. | Determine reason and correct. |
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| unbalanced if three phase.) | ||
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| 3. | Overload protector defective. | 3. | Check current , replace protector. |
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| 4. | Run capacitor defective. | 4. | Determine reason and replace. |
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| 5. | Excessive discharge pressure. | 5. | Check ventilation, restrictions in |
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| cooling medium, restrictions in |
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| 6. | Suction pressure too high. |
| refrigeration system. |
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| 6. | For salad models, temperature | ||
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| control differential set to close- |
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| increase differential. |
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| 7. | Compressor too hot - return gas. | 7. | Check refrigerant charge (fix leak) |
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| add if necessary. |
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| 8. | Compressor motor has a winding | 8. | Replace compressor. |
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| shorted. |
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5. | Compressor runs but short | 1. | Overload protector. | 1. | See (4) above. |
| cycles on... | 2. | Thermostat. | 2. | Differential set too close - widen. |
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| 3. | High pressure | 3. | a. Check air or water supply to |
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| a. Insufficient air or water supply. |
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| b. Overcharge. |
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| b. Recover refrigerant and recharge. | |
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| c. Air in system. | 4. |
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| 4. | Low pressure | a. Replace. | |
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| a. Liquid line solenoid leaking. |
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| b. Compressor valve leak. |
| b. Replace. |
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| c. Undercharge. |
| c. Fix leak, add refrigerant. |
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| d. Restriction in expansion |
| d. Replace device. |
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| device. |
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6. | Condensing unit operates for | 1. | Shortage of refrigerant. | 1. | Fix leak, add charge. |
| prolonged periods or | 2. | Control contacts stuck or frozen | 2. | Clean contacts or replace control. |
| continuously. |
| closed. | 3. | Allow unit sufficient time for |
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| 3. | Excessive heat load placed into | ||
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| cabinet. |
| removal of latent heat. |
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| 4. | Prolonged or too frequent door | 4. | Plan or organize schedule to |
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| openings. |
| correct condition. |
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| 5. | Evaporator coil iced. | 5. | Defrost. |
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| 6. | Restriction in refrigeration | 6. | Determine location and remove. |
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| system. |
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| 7. | Dirty condenser. | 7. | Clean condenser. |
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| 8. | Filter dirty. | 8. | Clean or replace. |
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