BoilerFaultCodesTechnical description
Fault/Lockout - Ignition failure or sensing/spark electrode and lead fault.
What causes this fault?
This fault occurs when the boiler tries to ignite but fails to create a stable flame, causing the system to shut down for safety. The most common reasons are a worn-out ignition spark, a blocked gas supply, or an internal sensor failing to detect that the burner has actually lit. In some cases, a fault with the main control board means the boiler isn't sending the correct signal to start the ignition process.
This issue can be more frequent during extreme cold spells if the external gas regulator freezes or if there is a sudden drop in local gas pressure.
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.