Baxi Baxi 600/800/Assure System 2 and 600 Combi 2 platform fault E.04.54

Fault in gas valve control circuit

Gas boiler

What it means

Fault in gas valve control circuit

Likely causes

  1. Gas valve wiring fault
  2. Gas valve or PCB fault
  3. Flue components incorrectly assembled, fixed or supported
  4. Flue or terminal obstructed
  5. Products of combustion and inlet air mixing
  6. Burner seals, internal flue seals, door or case seals unsound
  7. Newly fitted gas valve not yet calibrated
  8. Gas valve out of adjustment
  9. CO2 at minimum heat input out of specified range
  10. CO2 at maximum heat input out of specified range

Where to start

  1. Check the wiring on the gas valve
  2. Set boiler to maximum rate and allow combustion to stabilise. Do not insert probe to avoid 'flooding' the analyser.
  3. Perform Flue Integrity Combustion Check: insert analyser probe into air inlet test point, allow reading to stabilise.

The full answer, free

  • 47 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 77), right under the answer

Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.

From the Baxi manual for the Baxi 600/800/Assure System 2 and 600 Combi 2 platform. Check the model on the data plate before you order parts.

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