BoilerFaultCodesTechnical description
Ignition fault (lockout) Failed to light
What causes this fault?
This fault occurs when the boiler attempts to ignite but cannot confirm a stable flame is present. It is usually caused by a lack of gas reaching the burner, worn-out spark electrodes, or a buildup of debris on the internal components that prevents the ignition process from completing safely.
This fault can be more frequent during the first cold snap of autumn when old electrodes or gas valves struggle to operate after being idle over the summer.
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 →