BoilerFaultCodesYour boiler has lost its flame while running and is struggling to relight itself.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Failure to re-ignite
What causes this fault?
This fault occurs when the boiler successfully lights but the flame goes out unexpectedly while the system is running. The most common reasons include a temporary interruption in the gas supply, a blocked condensate drain, or internal components like electrodes being too dirty to detect the flame. If the boiler cannot sense a stable flame after several attempts, it will shut down for safety.
This fault is more common in winter, as the external condensate pipe can freeze and cause a backup that extinguishes the flame.
DIY fix possible
Check that your gas emergency control valve is open and you have credit on your gas meterPress and hold the 'Reset' button (flame symbol with a cross) for one secondEnsure the white plastic condensate pipe leading outside isn't frozen if it is very cold
Find a Gas Safe engineer
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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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