BoilerFaultCodesTechnical description
Flame not detected. Gas present and at correct pressure. Combustion CO2 level. Condition of flue. Ignition electrodes. Ignition harness and connections. Flame sense harness, cables and connections. Gas valve. Otherwise replace control board.
What causes this fault?
This fault occurs when the boiler's control system fails to detect a flame after several ignition attempts. The most common reasons include a lack of gas reaching the burner, worn-out ignition components that can't create a spark, or a sensor that is too dirty to 'see' the flame even if it has lit.
This fault is frequently seen during extreme cold spells, as a frozen condensate pipe can back up and prevent 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.