Heat pumps
15 Field cases
- Ground Loop Antifreeze Concentration Insufficient — Freezing / Poor Heat Transfer
- Heating COP Drop at Low Outdoor Temp (Below -10°C)
- Discharge Air Temperature Below 40°C During Heating
- Excessive Frosting on Air-Source Outdoor Unit (Defrost Failure)
- Auxiliary Electric Heater (Backup Heater) Malfunction
- Refrigerant Undercharge/Overcharge — Winter-Specific Symptoms
- Cold Air Complaint During Reverse-Cycle Defrost
- Ice Buildup Under Outdoor Fan After Defrost — Drain Pan Heater Failure
- Defrost Entry/Exit Condition Error
- Excessive Defrost Frequency
- Hot Gas Defrost Valve Stuck
- 4-Way Valve Partial Switching — Heating/Cooling Mode Change Failure
- EEV Hunting — Unstable Superheat Control
- EEV Stepper Motor Miscalibration — Incorrect Valve Opening
- Ground Loop Flow Reduction — Air Entrainment / Cavitation