BoilerFaultCodesYour boiler's burner stays lit even when it should turn off, meaning it isn't responding to your thermostat or timer settings.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: The burner will remain alight until switched off by the control thermostat, any remote control or the programmer.
What causes this fault?
This fault occurs when the boiler loses its ability to regulate the flame, causing the burner to stay lit regardless of your heating settings. The most common reason is a malfunctioning main circuit board or a faulty gas valve that has become stuck in the open position. It can also be caused by a wiring error in your external thermostat or programmer that is continuously sending a 'heat on' signal.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Burner On neon off — no call-out fees, no surprises.
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