BoilerFaultCodesYour boiler was working but the flame has unexpectedly gone out, causing the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flame failure during operation
What causes this fault?
This fault happens when your boiler successfully starts up but the flame unexpectedly goes out while it is running. It is usually caused by an interruption in the gas supply, a build-up of carbon on the sensing electrodes, or a blockage in the pipe that carries away waste liquids. When the boiler's internal sensors stop detecting a flame, the system shuts down as a safety precaution.
This fault is more common in freezing winter temperatures, as the external condensate pipe can freeze and cause a backup that puts the flame out.
DIY fix possible
Check if other gas appliances like your hob are working to ensure gas is reaching the propertyCheck your prehistoric or smart gas meter to ensure you haven't run out of creditPress the reset button (represented by a flame with a line through it) for one second to see if the boiler restarts
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F.29 — no call-out fees, no surprises.
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