Table 19 Ð Troubleshooting
SYMPTOMS |
| CAUSE |
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| REMEDY | |||
COMPRESSOR DOES |
| Power line open |
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| Reset circuit breaker. | |||
NOT RUN |
| Control fuse open |
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| Check control circuit for ground or short. | ||||
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| Replace fuse. | ||
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| Move | ||||||||
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| tripped |
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| position then back to RUN or CCN position. | |||
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| Tripped power breaker |
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| Check the controls. Find cause of trip | |||||
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| and reset breaker. | ||
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| Loose terminal connection |
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| Check connections. | |||||
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| Improperly wired controls |
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| Check wiring and rewire. | |||||
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| Low line voltage |
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| Check line voltage. Determine location | |||
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| of voltage drop and remedy de®ciency. | ||
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| Compressor motor defective |
| Check motor winding for open or short. | |||||||
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| Replace compressor if necessary. | ||
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| Seized compressor |
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| Replace compressor. | ||||
COMPRESSOR CYCLES OFF |
| Loss of charge |
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| Repair leak and recharge. | |||
ON LOW PRESSURE |
| Bad transducer |
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| Replace transducer. | |||
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| Low refrigerant charge |
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| Add refrigerant. | |||||
COMPRESSOR SHUTS DOWN |
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| Replace control. | ||||||||
ON HIGH PRESSURE |
| Compressor discharge valve partially closed |
| Open valve or replace if defective. | |||||||
CONTROL |
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| Condenser fan(s) not operating |
| Check wiring. Repair or replace motor(s) | ||||||||
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| if defective. | ||
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| Condenser coil plugged or dirty |
| Clean coil. | |||||||
UNIT OPERATES LONG OR |
| Low refrigerant charge |
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| Add refrigerant. | |||||
CONTINUOUSLY |
| Control contacts fused |
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| Replace control. | |||||
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| Partially plugged or plugged expansion |
| Clean or replace. | |||||||
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| valve or ®lter driver |
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| Defective insulation |
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| Replace or repair. | ||||
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| Service load |
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| Keep doors and windows closed. | |||
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| Inefficient compressor |
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| Check valves. Replace if necessary. | |||||
SYSTEM NOISES |
| Piping vibration |
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| Support piping as required. | |||
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| Expansion valve hissing |
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| Add refrigerant. | |||||
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| Check for plugged liquid line ®lter drier. | ||
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| Compressor noisy |
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| Check valve plates for valve noise. | ||||
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| Replace compressor (worn bearings). | ||
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| Check for loose compressor holddown bolts. | ||
COMPRESSOR LOSES OIL |
| Leak in system |
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| Repair leak. | |||
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| Mechanical damage (blown piston or |
| Repair damage or replace compressor. | |||||||
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| broken discharge valve) |
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| Crankcase heaters not energized |
| Replace heaters, check wiring and | |||||||
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| during shutdown |
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| crankcase heater relay contacts. | |||
FROSTED SUCTION LINE |
| Expansion valve admitting either too |
| Check cooler and compressor thermistors. | |||||||
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| much or too little refrigerant |
| Test EXV. | |||||||
HOT LIQUID LINE |
| Shortage of refrigerant due to leak |
| Repair leak and recharge. | |||||||
FROSTED LIQUID LINE |
| Shutoff valve partially closed or restricted |
| Open valve or remove restriction. | |||||||
COMPRESSOR DOES NOT |
| Burned out coil |
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| Replace coil. | |||
UNLOAD |
| Defective capacity control valve |
| Replace valve. | |||||||
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| Miswired solenoid |
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| Rewire correctly. | ||||
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| Weak, broken, or wrong valve body spring |
| Replace spring | |||||||
COMPRESSOR DOES NOT |
| Miswired solenoid |
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| Rewire correctly. | ||||
LOAD |
| Defective capacity control valve |
| Replace valve. | |||||||
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| Plugged strainer (high side) |
| Clean or replace strainer. | |||||||
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| Stuck or damaged unloader piston or |
| Clean or replace the necessary parts. | |||||||
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| piston ring(s) |
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EXV Ð Electronic Expansion Valve |
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| Table 20 Ð Standard and Accessory Unloaders | |||||||||
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| NO. OF ACCESSORY | ||||
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| UNIT |
| NO. OF STANDARD |
| UNLOADERS | |||||
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| UNLOADER(s) |
| PERMITTED |
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| Circuit A | Circuit B |
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| 1 |
| 1 |
| 1 or 2 | ||
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| 2 |
| 1 |
| 1 |
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| 0 |
| 1 |
| 1 |
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*And associated modular units.
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