TROUBLESHOOTING (cont)
| PROBLEM |
| SOLUTION |
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COMPRESSOR CYCLES ON |
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Air¯ow Restricted |
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1. | Coil iced up. | 1. | Check refrigerant charge. |
2. | Coil dirty. | 2. | Clean coil ®ns. |
3. | Air ®lters dirty. | 3. | Clean or replace ®lters. |
4. | Dampers closed. | 4. | Check damper operation and position. |
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1. | Electrical connections loose. | 1. | Tighten all connections. |
2. | Fan relay defective. | 2. | Replace relay. |
3. | Motor overload open. | 3. | Power supply. |
4. | Motor defective. | 4. | Replace motor. |
5. | Fan belt broken or slipping. | 5. | Replace or tighten belt. |
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COMPRESSOR RUNNING BUT COOLING INSUFFICIENT |
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Suction Pressure Low |
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1. | Refrigerant charge low. | 1. | Add refrigerant. |
2. | Head pressure low. | 2. | Check refrigerant charge. |
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| Check |
3. | Air ®lters dirty. | 3. | Clean or replace ®lters. |
4. | Expansion valve power head defective. | 4. | Replace power head. |
5. | Indoor coil partially iced. | 5. | Check |
6. | Indoor air¯ow restricted. | 6. | Remove obstruction. |
Suction Pressure High |
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1. | Unloaders not functioning. | 1. | Check unloader adjustments. |
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| Check unloader setting. |
2. | Compressor valve defective. | 2. | See compressor service literature. |
3. | Heat load excessive. | 3. | Check for open doors or windows in vicinity of fan coil. |
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UNIT OPERATES TOO LONG OR CONTINUOUSLY |
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1. | Low refrigerant charge. | 1. | Add refrigerant. |
2. | Control contacts fused. | 2. | Replace control. |
3. | Air in system. | 3. | Purge and evacuate system. |
4. | Partially plugged expansion valve or ®lter drier. | 4. | Clean or replace. |
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SYSTEM IS NOISY |
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1. | Piping vibration. | 1. | Support piping as required. |
2. | Compressor noisy. | 2. | Check valve plates for valve noise. Replace compressor if |
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| bearings are worn. |
COMPRESSOR LOSES OIL |
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1. | Leak in system. | 1. | Repair leak. |
2. | Crankcase heaters not energized during shutdown. | 2. | Check wiring and relays. Check heater and replace if |
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| defective. |
3. | Improper interconnecting piping design. | 3. | Check piping for oil return. Replace if necessary. |
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FROSTED SUCTION LINE |
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Expansion valve admitting excess refrigerant. | Adjust expansion valve. | ||
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HOT LIQUID LINE |
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1. | Shortage of refrigerant due to leak. | 1. | Repair leak and recharge. |
2. | Expansion valve opens too wide. | 2. | Adjust expansion valve. |
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FROSTED LIQUID LINE |
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1. | Restricted ®lter drier. | 1. | Remove restriction or replace. |
2. | Liquid line solenoid valve partially closed. | 2. | Replace valve. |
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COMPRESSOR WILL NOT UNLOAD |
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1. | Defective unloader. | 1. | Replace unloader. |
2. | Defective capacity control solenoid valve (if used). | 2. | Replace valve. |
3. | Miswired capacity control liquid line solenoid (if used). | 3. | Rewire correctly. |
4. | Weak, broken, or wrong valve body spring. | 4. | Replace spring. |
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COMPRESSOR WILL NOT LOAD |
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1. | Miswired capacity control liquid line solenoid (if used). | 1. | Rewire correctly. |
2. | Defective capacity control solenoid valve (if used). | 2. | Replace valve. |
3. | Plugged strainer (high side). | 3. | Clean or replace strainer. |
4. | Stuck or damaged unloader piston or piston ring(s). | 4. | Clean or replace the necessary parts. |
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