BoilerFaultCodesYour boiler has lost its flame while running and is now unable to relight itself to provide heat or hot water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flame goes off during operation and subsequent ignition attempts failed
What causes this fault?
This fault occurs when your boiler successfully starts but cannot maintain a steady flame while it is running, leading the system to shut down for safety. The most common reasons include a temporary interruption in your gas supply, a build-up of carbon on the ignition sensors, or a component failure that prevents the correct mix of gas and air from reaching the burner.
This issue is more frequent during extreme cold spells, as freezing temperatures can cause external gas regulators to stick or condensate pipes to freeze and back up into the boiler.
DIY fix possible
Check if other gas appliances in your home, like a hob, are working to ensure gas is reaching the propertyCheck if your gas meter has credit (if using a pre-payment meter)If it is freezing outside, check if the white plastic condensate pipe leading outdoors is frozen and thaw it with warm waterPress the reset button (indicated by a flame symbol with a cross) for one second
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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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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