Your boiler has tried to light several times but cannot establish a flame, meaning your heating and hot water will not work until it is reset or repaired.

Ignition lockout

What causes this fault?

This fault occurs when the boiler's internal computer senses that a flame has not been successfully lit after several attempts. The most common reasons include a lack of gas reaching the burner, a dirty or worn spark plug that can't create a flame, or an issue with the gas valve not opening correctly.