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5238

Warning DHW temp. sensor TW1 short circuit

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

What does 5238 mean?

The circuit for the hot water sensor TW1 is shorted, indicated by resistance below 390 Ohm.

Common Causes

  • Hot water sensor TW1 shorted
  • Signal cable to TW1 shorted

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Disconnect the sensor from the installer board.

  2. 2

    Measure the resistance and compare it to the sensor table in the documentation.

  3. 3

    Repair the cable or replace the sensor if necessary.

  4. 4

    If the warning persists after sensor replacement, the installer board may be defective and require replacement.

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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