Medium
1 16 on Ariston Clas HE Evo

Your boiler has detected that the external temperature safety switch—often used for underfloor heating—has been triggered, causing the system to stop heating to prevent damage.

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

floor thermostat contact open

Engineer required

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

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Related fault codes

1 18View →6 04View →

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