BoilerFaultCodesTechnical description
Burner does not start. No flame signal after the safety time has elapsed. (Reset required: Turn control knob 'Reset' to the right until 'CL' appears, then turn back).
What causes this fault?
This fault occurs when the boiler tries to ignite the gas to create a flame but fails to detect one within a safe time limit. The most common reasons include a lack of gas reaching the burner, worn-out ignition components that can't create a spark, or a dirty sensor that cannot 'see' the flame even if it has lit.
This fault is frequently seen during extreme cold snaps, as the external condensate pipe can freeze and block the system, preventing the boiler from lighting.
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.