Technical description
Ignition fault.
What causes this fault?
This fault occurs when the boiler's control system attempts to start a flame but fails to detect one after several attempts. The most common reasons are a lack of gas reaching the burner, worn-out ignition sparks that can no longer bridge the gap, or a carbon-coated sensor that cannot 'see' the flame once it has lit.
This fault can be more frequent during the first cold snap of autumn when internal components that have sat idle all summer finally seize or fail under heavy use.
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.