BoilerFaultCodesYour boiler has stopped working because one of its internal temperature sensors is providing an incorrect reading or has failed.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Sensor fault S1.
What causes this fault?
This fault occurs when the boiler's main control board detects a broken electrical circuit or an incorrect signal coming from the flow temperature sensor. The most common reason is that the sensor itself has developed an internal fault, though it can also be triggered by loose or corroded wiring in the harness. Because the boiler can no longer accurately monitor the heat of the water leaving the unit, it shuts down as a safety precaution.
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 F031 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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