Grant Aerona R290 fault P02

High pressure protection

Heat pump

What it means

High pressure protection fault (HP1), occurring during operation, due to high refrigerant pressure detected.

Likely causes

  1. Water flow is low
  2. High pressure switch is faulty
  3. Refrigerant system is blocked

Where to start

  1. Check high pressure switch connection/operation
  2. Check whether the refrigerant system is blocked
  3. Access 'heat pump schematic' screen (steps 1-3 in section 18.4.1) to view fan, pump and compressor status and water temperatures

The full answer, free

  • 10 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 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.

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