Medium
F.012 on Vaillant ecoTEC plus Combi

Your boiler is having difficulty reading the temperature of the water being heated for 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

The domestic hot water connection temperature sensor has short-circuited.

From this model's manual
Verified against the Vaillant Ecotec Plus installation & service manual, page 80.
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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Related fault codes

F.011View →F.013View →

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