Emergency
F.77 on Vaillant ecoTEC Plus 610

Your boiler has detected a potential blockage or mechanical issue with the system that manages exhaust gases, which has triggered a safety shutdown to prevent harmful gases from entering your home.

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

Fault:Condensateorsmoke | Noresponse,fluenon-returnflapdefective

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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