Emergency
HIGH SMOKE NUMBER on Worcester Bosch Utility

Your boiler is not burning its fuel properly, which is causing soot to build up and could potentially lead to harmful fumes entering 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

Air intake/flue blocked; Incorrect combustion settings; Oil pressure incorrect; Incorrect components used on combustion head; Faulty nozzle

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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