Vaillant aroTHERM fault codes

What each code means, from Vaillant aroTHERM's own service literature, and which UK models it applies to.

Vaillant aroTHERM heat pumps

F.022Heating water pressure too low9 models F.732Compressor outlet temperature too high9 models F.731High-pressure switch open9 models F.729Compressor outlet temperature too low9 models F.718Fan unit 1 blocked9 models F.785Fan unit 2 blocked9 models F.788Building circuit pump fault9 models F.7554-port valve position incorrect9 models F.817Frequency converter (inverter) fault9 models F.818Frequency converter: mains voltage fault9 models F.1117Compressor phase failure9 models F.514Compressor inlet temperature sensor9 models F.517Compressor outlet temperature sensor9 models F.546High-pressure sensor fault9 models F.774Air inlet temperature sensor9 models F.520Building circuit flow temperature sensor9 models F.519Building circuit return temperature sensor9 models F.582Electronic expansion valve fault9 models F.073Building-circuit water pressure sensor fault9 models F.526EEV outlet temperature sensor fault9 models F.585Condenser outlet temperature sensor fault9 models F.825Condenser inlet temperature sensor fault9 models F.821Immersion heater flow sensor fault9 models F.723Building circuit: pressure too low9 models F.820Connection fault: building circuit9 models F.733Evaporation temperature too low9 models F.734Condensation temperature too low9 models F.735Evaporation temperature too high9 models F.737Condensation temperature too high9 models F.741Building-circuit return temperature too low (during de-icing)9 models F.819De-icing time too long9 models F.752Frequency converter not recognised9 models F.7534-port valve position not correct9 models F.1120Heating rod: phase failure9 models F.1100Immersion heater: safety cut-out9 models F.042Coding resistor fault9 models

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Other makes

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