Technical description
False Flame Lockout
What causes this fault?
This fault occurs when the boiler's internal sensor detects an electrical signal suggesting a flame is present before the ignition process has even started. The most common reason is a contaminated or damaged flame sensor, though moisture on the internal electronics or a malfunctioning control board can also trick the system into seeing a 'ghost' flame.
This fault can be more frequent during periods of high humidity or heavy rain, as moisture ingress into the flue or dampness within the casing can cause electrical interference with the flame sensing circuit.
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.