Medium
S.39 on Vaillant ecoTEC plus Aquaplus

Your boiler has detected that the water temperature in your underfloor heating circuit is too high, so it has temporarily shut down to prevent damage to your flooring.

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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Related fault codes

S.36View →F.22View →

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