BoilerFaultCodesYour boiler has lost its flame while running and is unable to automatically restart, likely because the gas flow is being interrupted.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Operating failure: Ignit. unsuccessful - Gas supply interrupted intermittently. Re-ignition failed.
What causes this fault?
This fault occurs when your boiler successfully starts but lose its flame while it is trying to heat your home or water. The most common reasons are a temporary drop in gas pressure, a build-up of debris on the burner, or a faulty internal component that can no longer detect the flame. If it happens during very cold weather, it may also be caused by a frozen external pipe blocking the system's drainage.
This fault is more common during extreme cold snaps, as the boiler's condensate pipe can freeze and cause the flame to extinguish.
DIY fix possible
Check if other gas appliances in your home, like a hob, are working correctly.If you have a prepayment meter, ensure you have sufficient credit.During freezing weather, check if the white condensate pipe leading outside is frozen and thaw it with warm water.Press 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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