Medium
F.317 on Vaillant ecoTEC Plus 836

Your boiler is struggling to detect the flow of water needed to heat your taps, which will likely prevent you from getting hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Fault in the electrical connection for the volume flow sensor in the domestic hot water circuit is implausible.

From this model's manual
Verified against the Vaillant Ecotec Plus installation & service manual, page 89.
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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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