Grant Aerona R290 fault P08
Middle pressure protection
Heat pumpWhat it means
Middle pressure protection fault due to incorrect switch connection or faulty refrigerant PCB.
Likely causes
- Middle pressure switch not connected correctly
- The refrigerant PCB is faulty
Where to start
- Check connections on sensor and refrigerant PCB
- Check refrigerant PCB
The full answer, free
- How to put it right, step by step
- The manual page for this fault (page 58), 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 Grant manual for the Aerona R290. Check the model on the data plate before you order parts.
Other Grant Aerona R290 fault codes
- 1Pump over-voltage protection
- 2Pump under-voltage protection
- 3Pump over-current protection
- 4Pump light-load protection
- 5Pump phase loss protection
- 6Pump block protection
- 7Pump over-temperature protection
- E01Connection fault between wiring centre and heat pump
- E02Discharge temperature sensor failure (TP)
- E03Coil temperature sensor failure (T3)
- E04Ambient temperature sensor failure (T4)
- E05Liquid pipe temperature sensor failure (T5)
- E06Return air temperature sensor failure (TH)
- E07Water tank temperature sensor failure (TW)
- E08Outlet water temperature sensor failure (TA)
- E09Outlet water temperature sensor failure (TB)
- E10Communication failure between hydraulic PCB and refrigerant PCB
- E13Discharge pressure sensor fault
- E15DC bus voltage is too low
- E16DC bus voltage is too high
- E17AC current protection (input current)
- E18IPM module is abnormal
- E19PFC abnormal
- E20Compressor failed to start