Emergency
YELLOW FLAMES / SOOT FORMED on Chaffoteaux Britony II 50FF

Your boiler is not burning fuel correctly, which is creating dangerous soot and could potentially release harmful carbon monoxide into your home.

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.

Technical description

I) Heating body fins blocked; II) Primary air supply restricted; III) Wrong injectors

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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