Grant Aerona R290 fault E27

PFC module temperature sensor is abnormal

Heat pump

What it means

Temperature sensor for PFC module detected abnormal reading.

Likely causes

  1. Cables incorrectly connected
  2. Refrigerant & Drive PCB is faulty
  3. Outdoor air temperature (T4) below 7°C combined with low return (TA) or flow (TB) water temperature below 6°C

Where to start

  1. Check all connections from the Refrigerant PCB (or Refrigerant & Drive PCB for the 16kW model)
  2. Check ambient temperature sensor (T4) reading
  3. Check inlet/outlet water temperature

The full answer, free

  • 21 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 60), 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.

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