Fault Codes / Bosch / A21 (1001)

Bosch A21 (1001)

High

Compress — No communication system controller ↔ remote control.

Bosch A21 (1001): No communication system controller ↔ remote control. This fault noticeably affects operation.

Possible causes

Poor EMS connection display ↔ board.

Check steps

Check both ends of EMS cabling.
Check room sensor/remote control.

Affected parts

EMS-Leitung
Fernbedienung

Safety note

Low voltage — work carefully.

Source: Bosch resmi servis kılavuzu — Alarm List A/W Split (8754) p.1: code 1001/A21/A22/A23/A24 'No communication betw. system controller and remote control.' Exact match.

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

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