BoilerFaultCodesYour boiler was running but the flame has unexpectedly gone out, causing the system to stop working as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flame loss during operation
What causes this fault?
This fault occurs when the boiler successfully lights but cannot maintain a steady flame, causing the system to shut down for safety. The most common reasons include a blockage in the condensate drainage pipe, an unstable gas supply, or a buildup of carbon on the electrodes that monitor the flame.
This fault is significantly more common during freezing winter temperatures, as the external condensate drainage pipe can freeze and cause water to back up into the boiler.
DIY fix possible
Check that your gas emergency control valve is open and you have credit on your gas meter.Check if other gas appliances in your home, such as a hob, are working correctly.Press the reset button (indicated by a flame with a line through it) for five seconds.
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 F29 — no call-out fees, no surprises.
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Glow-worm Flexicom 18sx is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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