Medium
1 16 on Ariston Microsystem 15

Your boiler has detected that the external temperature safety switch, often connected to underfloor heating, has cut the connection to the system.

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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