Emergency
HIGH SMOKE NUMBER on Worcester Bosch Greenstar Utility

Your boiler is burning fuel improperly, which indicates the system is producing harmful exhaust fumes and needs an urgent inspection to prevent carbon monoxide buildup.

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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