Baxi Baxi 200/400/600/800 Combi 2 & System 2 Baxi 600/800/Assure System 2 and 600 Combi 2 platform fault E.04.17

Fault in gas valve control circuit

Gas boiler

What it means

Permanent fault requiring reset, indicating a fault in the gas valve control circuit attributed to a main PCB error.

Likely causes

  1. Main PCB error
  2. CO2 value out of specified range at maximum heat input
  3. CO2 value out of specified range at minimum/reduced heat input

Where to start

  1. With the boiler off turn the gas flow adjustment screw (V) fully clockwise until flush with the plastic tube (left-hand thread)
  2. Turn the gas flow adjustment screw (V) anticlockwise by the number of turns shown in the table to set combustion correctly
  3. Ensure there is a demand to turn the boiler on; if the boiler ignites go to step 7, otherwise proceed to steps 4-6

The full answer, free

  • 20 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 74), 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 200/400/600/800 Combi 2 & System 2 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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