Emergency
F.53 on Vaillant ecoTEC Pro / ecoTEC Plus Regular

Your boiler has detected an issue with the gas flow, meaning it cannot safely ignite or maintain a flame to heat 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.

What the manual says

Manufacturer manual

Gasvalveassemblymass flowunexpected

From this model's manual
Verified against the Vaillant Ecotec Pro Ecotec Plus Regular installation & service manual, page 61.
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.52View →F.54View →

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