BoilerFaultCodesYour boiler has failed to light because either the gas didn't ignite or a sensor has detected that the condensate drainage pipe is blocked.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Ignition failure/not flame sensed, condense sensor activated
What causes this fault?
This fault occurs when the boiler attempts to start but cannot safely confirm a flame is present. The most common reasons are that the gas supply isn't reaching the burner, the ignition electrodes are worn out, or the internal drainage pipe is backed up with water, which triggers a safety sensor to prevent an overflow.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze, causing a blockage that prevents the boiler from firing.
DIY fix possible
Check if your gas supply is active (e.g. check other gas appliances or your prepayment meter balance).Inspect the white plastic pipe leading outside for ice or blockages; if frozen, gently defrost it with warm (not boiling) water.Turn the mode selector dial to the 'RESET' position for a few seconds, then back to your desired setting.
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