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

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

floor thermostat contact open

From this model's manual
Verified against the Ariston E Combi One 24 installation & service manual, page 38.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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