Fault Codes / Airwell / P4

AI

Airwell P4

Critical

YHD — IPM protection / inverter fault.

Airwell P4: IPM protection / inverter fault. This fault typically halts operation and needs immediate attention.

Possible causes

IPM/IGBT faulty / compressor earth short.

Check steps

Power off: check compressor insulation (megger) & IPM.

Affected parts

Inverter-PCB
Verdichter

Safety note

High voltage! Let capacitors discharge before work.

Source: Airwell YHD/HZ Service Manual

Reviewed by Anıl Güzeldemir — in the refrigeration machine room since 2006, developer of Enthalio.

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Related fault codes

Communication error.E6 High pressure protection (outdoor).P0 Low pressure protection.P1 Compressor overcurrent.P2 Compressor startup failure.P6 Incorrect phase sequence / phase loss.P7