
Troubleshooting
Checklist
Problem | Heating | Cooling | Cause | Correction | |
| X | X | Main power off | Check fuses | |
No response to any | X | X | Defective control transformer | Replace | |
X | X | Broken or loose connection | Repair | ||
thermostat setting | |||||
X | X | Defective thermostat | Replace | ||
| |||||
| X | X | Transformer | Reset Transformer | |
Unit short cycles | X | X | Thermostat or sensor improperly located | Relocate | |
| X | X | Defective compressor overload | Replace (if external) | |
| X | X | Defective compressor contactor | Replace | |
Blower runs, but compressor does not | X | X | Supply Voltage too low | Correct | |
| X | X | Defective compressor capacitor | Replace | |
| X | X | Defective windings | Replace | |
| X | X | Limit switches open | Check cause/Replace or repair | |
| X | X | Dirty filter | Replace/clean | |
| X | X | Blower RPM too low | Correct | |
| X | X | Loss of conditioned air due to leaks in | Repair leaks | |
| ductwork | ||||
|
|
|
| ||
|
|
|
|
| |
|
| X | Introduction of excessively hot | Correct | |
| X |
| Introduction of excessively cold | Correct | |
| X | X | Low on refrigerant charge | Locate leak, repair and recharge by | |
| weight (not by superheat) | ||||
Insufficient capacity |
|
|
| ||
|
|
|
| ||
X | X | Restricted thermal expansion valve | Replace | ||
| |||||
| X | X | Defective reversing valve | Replace | |
| X | X | Thermostat improperly located | Relocate | |
| X | X | Unit undersized | Recalculate heat gains/losses | |
| X | X | Inadequate water flow | Increase GPM | |
| X | X | Scaling in heat exchanger | Clean or replace | |
|
| X | Water too hot | Decrease temperature | |
| X |
| Water too cold | Increase temperature | |
|
| X | Inadequate GPM | Increase water flow to unit | |
|
| X | Water too hot | Decrease temperature | |
High pressure switch open | X |
| Inadequate air flow | Check, clean blower and coil | |
X |
| Dirty filter | Clean/replace | ||
|
| ||||
| X | X | Overcharged with refrigerant | Decrease charge | |
| X | X | Defective pressure switch | Check or replace | |
|
| X | Trash in heat exchanger | Backflush | |
|
| X | Low water flow | Increase GPM | |
High head pressure | X | X | Overcharge of refrigerant | Decrease charge | |
X | X | Evacuate and recharge by weight | |||
| X | X | Water too hot | Decrease temperature | |
| X |
| Dirty filter | Clean / replace | |
| X |
| Inadequate air flow | Check, clean blower and coil | |
| X | X | Undercharged | Locate leak, repair and recharge | |
Low suction pressure | X | X | Restricted thermal expansion valve | Repair / replace | |
| X | Inadequate air flow | Check, clean blower and coil | ||
|
| X | Dirty filter | Clean/replace | |
| X |
| Inadequate GPM | Increase GPM | |
| X |
| Inadequate GPM | Increase GPM | |
| X |
| Water too cold | Increase temperature | |
Low Pressure switch open |
| X | Inadequate air flow | Increase CFM | |
| X | Dirty filter | Clean/replace | ||
| X | X | Undercharged with refrigerant | Increase charge | |
| X | X | Defective pressure switch | Replace | |
| X | X | Heat transfer fluid too cold | Raise water temperature |
34 |