Emergency
FA on Worcester Bosch CDi Classic

Your boiler is still detecting a flame even after it has been told to shut down, which indicates a potential safety issue with the gas supply inside the unit.

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

Flame detected after gas shut off – the gas valve needs checking – hire a Gas Safe installer.

From this model's manual
Verified against the Worcester Bosch Cdi Classic installation & service manual, page 54.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal sensors continue to detect a flame even though the system has commanded the gas supply to stop. The most common reason is a gas valve that hasn't closed fully or a faulty sensor sending an incorrect signal to the main control board.

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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