SECTION 5
TROUBLESHOOTING
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| REMEDY/ |
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CONDITION | POSSIBLE CAUSE | REFERENCE |
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5.1 UNIT WILL NOT START OR STARTS THEN STOPS |
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| External power source OFF | Turn on |
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No power to unit | Check |
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Circuit breaker tripped or OFF | Check |
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| Modular transformer not connected | 6.22 |
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Loss of control power Loss of | Circuit breaker OFF or defective | Check |
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Control transformer (TR) defective | Replace |
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control power in respective branch |
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Fuse (F3) blown | Check |
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of control circuit only |
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Check |
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| Evaporator fan motor internal protector open | 6.15 |
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Loss of control power in respective | Condenser fan motor internal protector open | 6.18 |
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Compressor internal protector open | 6.7 |
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branch of control circuit only |
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High pressure switch open | 5.7 |
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| Heat termination thermostat (HTT) open | Replace |
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| Low line voltage | Check |
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| Single phasing | Check |
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Compressor hums, but does not | Shorted or grounded motor windings | 6.7 |
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start | Compressor seized | 6.7 |
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| Contactor (SC) shorting (in high speed mode of | Check |
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| compressor only) |
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Compressor will occasionally | Compressor speed change (On units with | Normal |
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compressor) |
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5.2 UNIT RUNS BUT HAS INSUFFICIENT COOLING |
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Compressor | Compressor valves defective | 6.7 |
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| Abnormal pressures | 5.7 |
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| Temperature controller malfunction | 5.9 |
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Refrigeration System | Evaporator fan or motor defective | 6.15 |
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Suction modulation valve malfunction | 6.25 |
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| Suction solenoid valve malfunction | 2.10/6.24 |
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| Condenser Pressure Transducer (CPT) defective | Check |
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| Shortage of refrigerant | 6.6 |
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5.3 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING |
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Container | Hot load | Normal |
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Defective box insulation or air leak | Repair |
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| Shortage of refrigerant | 6.4/6.6 |
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| Evaporator coil covered with ice | 5.6 | 5 |
| Evaporator coil plugged with debris | 6.13 | |
| SECTION | ||
| Evaporator fan(s) rotating backwards | 6.15/6.16 | |
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| Defective evaporator fan motor/capacitor | 6.15/6.16 |
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| Air bypass around evaporator coil | Check |
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Refrigeration System | Controller set too low | Reset |
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| Compressor service valves or liquid line shutoff valve | Open valves |
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| partially closed | completely |
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| Dirty condenser | 6.17 |
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| Compressor worn | 6.7 |
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| Current limit (Code 32) set to wrong value | 3.1.4 |
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| Suction modulation valve (SMV) malfunction | 6.25 |
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