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28

Error 28 - Flue NTC sensor Fault

Baxi · Duo-tec 2 Combi GA Boilers

What does 28 mean?

This error code indicates a problem with the Flue NTC (Negative Temperature Coefficient) sensor. The boiler's display will show the spanner symbol and the numeric error code, suggesting a sensor malfunction.

Common Causes

  • Faulty Flue NTC sensor
  • Damaged wiring to the sensor
  • Loose sensor connection or internal boiler issue

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Press the 'R' (reset) button firmly for several seconds to attempt to clear the fault.

  2. 2

    If the error persists, turn off the boiler's electrical supply at the isolation switch for 30 seconds, then turn it back on.

  3. 3

    If the fault code reappears, contact your installer or the Baxi service division ('heateam') for assistance.

Browse all codes in this manual (28)
Verified technical data. Last updated: April 2026

Related Faults

09Error 09 - Gas Valve Connection Cable Fault109Error 109 - Pre-circulation Fault110Error 110 - Safety Thermostat Activated
Source: Baxi Duo-tec 2 Combi GA Boilers
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