Emergency
F16 on Vaillant ecoMAX Pro 18E

Your boiler has detected that a flame is still burning inside even after it should have turned off, which is a safety concern that requires an immediate professional check.

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

Flame detection fault (flame presence >5 s after burner stop)

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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