BoilerFaultCodesYour boiler's internal sensor that monitors the temperature of the water returning to the unit has stopped communicating correctly, causing the system to shutdown for safety.
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 error – t-sensor damaged, short circuited, sensor damaged or wiring broken
What causes this fault?
This fault occurs when the boiler's internal computer loses the ability to read the temperature of the water coming back from your radiators. This is usually caused by the return sensor failing internally due to age or heat stress, or a loose connection in the wiring that prevents the signal from reaching the main control board.
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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