Technical description
If the reset neon lights, turn the boiler temperature control to '0' (off), wait 30 seconds, then repeat the lighting instructions.
What causes this fault?
This fault occurs when the boiler's internal safety sensors detect that the unit has become too hot or has failed to light after several attempts. The most common reasons are a temporary interruption in the gas supply, a build-up of debris on the ignition components, or a lack of water circulation preventing the heat from escaping the heat exchanger.
This issue often appears during the first cold spell of autumn when the boiler is pushed to work harder after being mostly idle over the summer.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.