BoilerFaultCodesTechnical description
Ionisation failure during boiler operation
What causes this fault?
This fault occurs when the boiler’s control system suddenly loses the electronic signal that confirms a flame is present while it is firing. It is often caused by a worn-out sensing probe that can no longer detect the heat, or an unstable gas supply that causes the flame to flicker and go out. In some cases, internal debris or a failing control board can prevent the boiler from verifying that it is safe to keep burning fuel.
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.
Find a Gas Safe engineer
Search the official register →