BoilerFaultCodesTechnical description
Boiler at lockout.
What causes this fault?
This fault occurs when the boiler's control board fails to detect a stable flame after several attempts to ignite. The most common reasons are a worn-out ignition spark that can no longer light the gas or a dirty sensor that cannot 'see' the flame even if it is burning. In some cases, it may be caused by an inconsistent gas supply or a failing gas valve that isn't opening correctly.
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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