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28

28 — NTC fumes sensor faulty

Baxi · Duotec+ GA Compact Boilers

What does 28 mean?

The NTC fumes sensor, which measures the temperature of the exhaust fumes, is defective or has a wiring problem. This can be a safety concern.

Common Causes

  • Faulty NTC fumes probe
  • Broken or shorted probe wiring

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Press and hold down the Reset button for 2 seconds to try clearing the fault.

  2. 2

    Ensure the boiler's power supply is stable.

  3. 3

    If the fault persists, contact an Authorised Service Centre to check the probe and wiring.

Browse all codes in this manual (37)
Verified technical data. Last updated: April 2026

Related Faults

0909 — Gas valve connection error1010 — External probe sensor faulty109109 — Air in boiler circuit (temporary fault)
Source: Baxi Duotec+ GA Compact Boilers
Open Manual (Page 16)Search more codes in this manual