Medium
F.86 on Vaillant ecoTEC plus System

Your boiler has detected that the external sensor monitoring your underfloor heating system is not communicating correctly, meaning your underfloor heating may not turn on or regulate its temperature properly.

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

Underfloor heating contact fault

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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