Emergency
F.25 on Vaillant ecoTEC Plus 610

Your boiler has detected that the exhaust gases are becoming dangerously hot, or a safety sensor connection has been disconnected, so it has shut down to prevent damage.

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

Safetyswitch-off:Fluegastemperaturetoohigh | Breakinplugconnectionforoptionalfluegassafetycut-out(STB),breakincableharness

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

F.23View →F.24View →

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