BoilerFaultCodesTechnical description
False flame lockout
What causes this fault?
This fault occurs when the boiler's control system detects an electrical signal suggesting a flame is present even though no gas is flowing. The most common reason is a contaminated or damaged flame sensing electrode sending a false signal, or moisture within the casing causing a short circuit. In some cases, the main circuit board may be failing and misinterpreting these electrical signals, leading to an immediate safety shutdown.
This issue can be more frequent during periods of high humidity or heavy rain, as internal dampness can interfere with the sensitive flame detection electronics.
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.