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5252

Warning Z1 Restr. in flow rate btw. outdoor and ind. unit (check strainer)

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

What does 5252 mean?

A restriction in the flow rate between the outdoor and indoor units is detected. This is indicated by a delta >13K in heating mode or >7K in cooling mode.

Common Causes

  • Bad circulation in the heating carrier/heating system

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the adjustment valves and thermostats for the heating system.

  2. 2

    Ensure the strainer is clean.

  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
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