Emergency
Red LED (illuminated) on Potterton Kingfisher MF RSL

Your boiler has switched itself off because it has detected an dangerous buildup of heat or a potential issue with the discharge of exhaust gases.

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

Indicates an overheat condition has occurred or a flue blockage (Products Discharge Safety Device TTB) has been detected.

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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