BoilerFaultCodesYour boiler has failed to ignite after several attempts, meaning it cannot provide heating or hot water until reset or repaired.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: ALTERNATING 'L' 'A' GO TO FRAME 87 OR 88
What causes this fault?
This fault occurs when the boiler tries to light the flame several times but fails to detect one, causing the system to shut down for safety. The most common reasons are a lack of gas supply to the unit, a worn-out ignition spark, or a faulty gas valve that isn't opening correctly. In some cases, a blocked flue or moisture on the internal components can also prevent the burner from staying lit.
This issue is more common during extreme cold snaps, as freezing temperatures can causes external gas meters to regulate poorly or condensate pipes to freeze and backup into the boiler.
DIY fix possible
Check if your gas prepay meter has credit and that the gas supply valve is openPress and hold the 'Mode' or 'Reset' knob for two secondsCheck that the white condensate pipe leaving the boiler is not frozen if it is winter
Find a Gas Safe engineer
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