BoilerFaultCodesYour boiler has detected a fault with a secondary temperature sensor that monitors water returning to the unit, causing it to stop operating 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: AUX return sensor failure
What causes this fault?
This fault occurs when the boiler's internal computer receives an incorrect or missing signal from the sensor that monitors water coming back from your radiators. This is usually caused by the sensor itself burning out or developing a physical defect, but it can also happen if the internal wiring has become loose or damaged. Because the boiler cannot accurately track the water temperature, it shuts down to prevent the system from overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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