Emergency
8.9 on Chaffoteaux Britony II 30FF

Your boiler is not burning gas correctly, which is creating soot and could be producing dangerous carbon monoxide.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Yellow Flames - Soot Formed

From this model's manual
Verified against the Chaffoteaux Britony Ii 30ff installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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