BoilerFaultCodesYour boiler has detected an issue with the safety switch protecting your underfloor heating system, causing it to stop running to prevent heat damage.
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: Fault: Underfloor heating contact
What causes this fault?
This fault occurs when the safety sensor designed to protect your underfloor heating detects that the water temperature is getting too high for your floor surface. Most often, this is caused by a failure in the external limit thermostat or a wiring issue between the underfloor heating controls and the boiler. It acts as a safety measure to prevent your floor from warping or cracking due to excessive heat.
This fault is most likely to appear at the start of autumn when the underfloor heating is switched on for the first time after being dormant all summer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like F.86 — no call-out fees, no surprises.
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