Emergency
F7 on Worcester Bosch 537i

Your boiler has detected a flame signal when it is supposed to be switched off, which is a significant safety precaution indicating a potential fault in the ignition or gas control system.

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 even though appliance is switched off.

From this model's manual
Verified against the Worcester Bosch 537i installation & service manual, page 46.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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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