Emergency
Pulsation on start on Worcester Bosch Greenstar 2000

Your boiler is struggling to breathe properly during startup, which prevents it from igniting smoothly and safely.

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

CF - Flue draught incorrect; Combustion settings incorrect; 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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