Emergency Lockout
FA on Worcester Bosch Greenstar 12i System

Your boiler is still detecting a flame even though it has tried to turn the gas supply off, which is a safety concern that requires an engineer.

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

Ionisation detected after burner stop

What causes this fault?

This fault occurs when the boiler's internal sensors continue to detect a flame even after the gas supply has been told to shut down. The most common reason is a gas valve that hasn't closed fully or a sensor that is incorrectly reporting a flame due to an electrical fault. Because this involves gas potentially flowing when it shouldn't, the boiler shuts down immediately as a safety precaution.

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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Related fault codes

EAView →C1View →F7View →

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