Emergency
F.027 on Vaillant ecoTEC Plus 836

Your boiler has detected that gas might be leaking internally while the burner is meant to be off, so it has shut down to keep your home safe.

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

Gas solenoid valve not leak-tight. A flame signal has been detected while the burner is off.

From this model's manual
Verified against the Vaillant Ecotec Plus installation & service manual, page 82.
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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Related fault codes

F.026View →F.028View →

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