Medium
S.39 on Vaillant aquaPLUS

Your boiler has paused because it detected that the water temperature going into your underfloor heating is too high, preventing damage to your floors.

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)

DIY fix possible

Check if your underfloor heating pump is runningEnsure any manual mixing valves for the underfloor heating are not set too highGently bleed air from the underfloor heating manifold to improve circulation

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Related fault codes

S.30View →F.20View →F.24View →

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