Bosch A01 (5903)

Critical

Compress — Fault in compressor motor control.

Bosch A01 (5903): Fault in compressor motor control. This fault typically halts operation and needs immediate attention.

Possible causes

Inverter/motor control disturbed.

Check steps

Check inverter & compressor connection.
Measure winding.

Affected parts

Inverter
Verdichter

Safety note

High voltage! Let capacitors discharge.

Source: Bosch/IVT/Buderus Compress Wärmepumpe Alarm-Tabelle (lvisawo.fi/jseducation.se resmi servis kılavuzu aynası) — Not independently re-verified -- third source inaccessible in this pass. Deferring to researcher's report.

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

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