Medium
F.86 on Vaillant ecoFIT Pure 425

Your boiler has lost the signal from the contact sensor that monitors your underfloor heating system, preventing it from heating that specific area.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Technical description

Fault: Underfloor heating contact

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.83View →F.84View →

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