BoilerFaultCodesYour boiler has detected a fault with an auxiliary temperature sensor, which means the system cannot accurately monitor the heat levels in certain parts of the unit.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: AUX output sensor error
What causes this fault?
This fault occurs when the boiler's control board loses communication with the auxiliary temperature sensor or receives an implausible reading. The most common reason is an electrical failure within the sensor itself, or damaged wiring that prevents the signal from reaching the main computer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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