BoilerFaultCodesYour boiler is receiving power and trying to work, but it has failed to start the burner to provide heat or hot water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Appliance on but not operating during demand
What causes this fault?
This fault occurs when the boiler is receiving an electrical signal to start, but the internal sequence to light the flame is interrupted. It is often caused by a lack of spark from the ignition electrode or a failure in the internal fan which clears waste gases. In some cases, the gas valve may not be opening correctly to allow fuel into the burner, preventing the boiler from firing up.
DIY fix possible
Check if your thermostat is set higher than the current room temperatureEnsure your external programmer or timer is set to 'On'Check that the gas supply to the property is turned onPress the reset button on the front of the boiler
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Light on — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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