How much does it cost to fix Chaffoteaux error code YELLOW FLAMES?

Typical repair cost for the Chaffoteaux YELLOW FLAMES fault is £150-350 including labour.

YELLOW FLAMES Emergency

Chaffoteaux YELLOW FLAMES Fault Code

Q: What does the Chaffoteaux YELLOW FLAMES fault code mean?

Your boiler is burning gas inefficiently, which is dangerous and can lead to the production of poisonous carbon monoxide gas.

Also written as YELLOWFLAMES — same fault.

The Chaffoteaux YELLOW FLAMES fault code means: your boiler is burning gas inefficiently, which is dangerous and can lead to the production of poisonous carbon monoxide gas.. It appears on 2 Chaffoteaux models in our database.

Technical description: i) Heating body fms blocked

Typical repair cost £150-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Chaffoteaux models that show the YELLOW FLAMES fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Chaffoteaux YELLOW FLAMES fault code information on this page is sourced and cross-checked against the official Chaffoteaux service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026