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| Troubleshooting | |
Table 14 Compressor and refrigeration system troubleshooting (continued) | |||
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Symptom | Possible Cause | Check or Remedy | |
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| Defective or improperly set expansion | Increase superheat or replace valve | |
| valve | ||
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Flooding | Evaporator fan motor or belt | Correct problem or replace fan motor and/ | |
or belts. | |||
| Low condensing pressure | Check head pressure control device | |
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| Slipping belts | Inspect and adjust | |
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| Compressor rotation in reverse | Check for proper power phase wiring to | |
Low compressor capacity or | direction. | unit and to compressor motor. | |
inability to pull down system | Leaking liquid line solenoid valve or dirt | Replace valve if clean; clean out valve if | |
| in valve | dirty. | |
Compressor noisy | Loose compressor or piping support | Tighten clamps. | |
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Pipe rattle | Loose pipe connections | Check pipe connections | |
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| Check setting of high and low pressure | |
Compressor running hot | Compression ratio too high | switches. Check condenser | |
plugged? Check that all evaporator and | |||
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| condenser fans are operating properly. | |
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| Check tubing to switch to see if clogged or | |
| crimped. Check for proper switch | ||
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| operation. | |
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| Check for leaks, fix, and add refrigerant on | |
| Insufficient refrigerant in system | air cooled unit. Evacuate and recharge | |
Compressor cycles intermittently |
| water/glycol unit. | |
| Suction service valve closed | Open valve. | |
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| Insufficient fluid flowing through | Adjust fluid regulating valve to condenser. | |
| condenser or clogged condenser, or | ||
| Flush the condenser. | ||
| dirty air cooled condenser coils | ||
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| Discharge service valve not fully open | Open valve | |
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| Faulty low pressure switch | Repair or replace. | |
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| Dirt or restriction in tubing to pressure | Check and clean tubing. | |
| stat | ||
Compressor cycles continually |
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Defective liquid line solenoid valve | Check valve and solenoid operator; | ||
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| replace if necessary. | ||
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| Plugged | Replace filter. | |
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| High discharge pressure | Check for loss of condenser water or | |
| blocked condenser fan or coil. | ||
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| Defective overload relay | Replace. | |
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| Reduce suction temperature by expansion | |
Compressor motor protectors | High suction temperature | valve adjustment or provide | |
tripping or cycling |
| desuperheating. | |
| Loose power or control circuit wiring | Check all power and control circuit | |
| connection | connections. | |
| Defective motor | Check for motor ground or short. Replace | |
| compressor, if either condition is found. | ||
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| Low line voltage | Check line voltage and determine location | |
| of voltage drop. | ||
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Compressor cycles on locked rotor | Compressor motor defective | Check for motor winding short or ground. | |
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| Single phasing | Check voltage across all 3 legs at | |
| contactor. Correct source problem. | ||
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| Check control panel for welded |
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Motor burnout | contactor contacts or welded overload | Replace defective components | |
| contacts |
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