BoilerFaultCodesYour boiler has stopped working because it can no longer accurately measure the temperature of the water coming back from your radiators.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return sensor fault
What causes this fault?
This fault occurs when the internal control board receives an incorrect or missing electrical signal from the sensor that monitors water returning from your radiators. The most common reason is that the sensor has physically failed or 'drifted' out of its correct range, but it can also be caused by loose wiring or moisture damaging the sensor's connection.
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 F11 — no call-out fees, no surprises.
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