BoilerFaultCodesTechnical description
Ionisation signal present even though burner is switched off
What causes this fault?
This fault occurs when the boiler's internal sensor detects a flame signal at a time when the gas should be completely shut off. The most common reason is a sensor that has become covered in carbon deposits or moisture, though it can also be caused by a gas valve that is failing to close fully or a fault within the main control board.
This issue can be more frequent during periods of high humidity or heavy rain, as moisture entering the air intake can interfere with the sensitive electronics of the ionisation probe.
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.
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