Medium
S.39 on Vaillant Thermocompact

Your boiler has temporarily stopped your underfloor heating because it detected that the water temperature in the pipes has become too hot for your floor surface.

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

Contact thermostat has been activated (under floor systems)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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