Ideal Logic Air fault 370-F9
Heat pump defrost thermistor fault
Heat pumpWhat it means
Heat Pump fault F9: defrost thermistor fault.
Likely causes
- Defrost thermistor failure or wiring fault
- Frost accumulation on evaporator due to outdoor humidity/temperature conditions
- Dwelling room temperature dropped to ≤8°C
- Dwelling ambient temperature at or below 8°C
- Ambient air temperature at or below 1°C
Where to start
- Identify 'Alarm' symbol to indicate a plant error
- Identify 'Maintenance/Special operations' symbol for maintenance message or special operation feedback
- Identify 'Event' symbol for event message from the plant
The full answer, free
- 22 more checks in order
- The readings and component tests from the manual
- How to put it right, step by step
- The manual page for this fault (page 103), right under the answer
Safety: Isolate the outdoor unit and any backup heater, and give the inverter capacitors time to discharge before you open the electrics. Anything on the refrigerant circuit needs F-gas certification.
From the Ideal manual for the Logic Air. Check the model on the data plate before you order parts.
Other Ideal Logic Air fault codes
- 134Re-occurring heat pump fault
- 366Room temp sensor fault
- 370-F15Heat pump air flow fault
- 370-F24Circulation pump error
- 370-F27No water flow fault
- 370-F3Heat pump inverter fault
- 370-F4Outdoor electrical filtering fault
- 7No heat pump starts exceeded
- 9.1.12BSB short circuit fault
- 9.1.16Source temperature too low fault
- 9.1.24Low mains voltage fault
- 9.1.26No outdoor connection fault
- 9.1.28Number of heat pump starts exceeded
- 9.1.29No central heating but hot water works OK