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5601 / 21

Alarm code 21 — Compressor blocked (IPM fault)

Bosch · Alarm List A/W Split (8754) 2018 01 10

What does 5601 / 21 mean?

The outdoor unit has detected an issue with the compressor. This alarm is triggered in the indoor unit if the outdoor unit alarm has been active for over 4 minutes.

Common Causes

  • Broken compressor
  • Too much refrigerant in the compressor

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Refer to separate error handling instructions for Split outdoor unit, error code 21.

  2. 2

    Check for proper installation and refrigerant levels.

  3. 3

    Contact a qualified technician.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

1001 / A21/A22/A23/A24Alarm A21/A22/A23/A24 — No communication between system controller and remote control1010 / A11Alarm A11 — No communication via EMS BUS connection1037Alarm 1037 — Outdoor temperature sensor faulty, heating standby mode active
Source: Alarm List A/W Split (8754) 2018 01 10
Open Manual (Page 25)Search more codes in this manual