BoilerFaultCodesTechnical description
No or insufficient ionisation flow.
What causes this fault?
This fault occurs when the boiler is unable to sense a flame after trying to ignite, causing it to shut down for safety. The most common reason is a worn-out sensing probe that can no longer detect heat, though it can also be caused by a blockage in the drainage system or an incorrect mix of gas and air.
This fault is more frequent during extreme cold spells, as the internal drain pipe can freeze and back up, preventing the boiler from maintaining a flame.
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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