BoilerFaultCodesYour boiler has stopped providing heat because a safety limit switch for your underfloor heating has been triggered or disconnected.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault: Underfloor heating contact. Underfloor heating contact open, sensor disconnected or defective
What causes this fault?
This fault occurs because a safety switch designed to protect your underfloor heating has detected that the water temperature is too high, causing it to cut power to the boiler. The most common reasons are a failed pump that isn't moving heat away quickly enough or a fault with the limit switch itself. It acts as a safety barrier to prevent the high heat from damaging your floor surfaces.
This fault is more common during the autumn and winter months when the underfloor heating is first switched on 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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