BoilerFaultCodesYour boiler has failed to ignite after several attempts, meaning it cannot create the flame needed to heat your home or water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: ALTERNATING 'H' 'F' GO TO FRAME 94
What causes this fault?
This fault occurs when the boiler fails to detect a flame after multiple ignition attempts, leading to a safety shutdown. The most common reasons include a lack of gas supply to the unit, a worn-out ignition spark electrode, or a blockage in the flue that prevents the necessary air-to-gas ratio for combustion.
This fault is frequently reported during extreme cold snaps, as the external condensate pipe can freeze and back up, preventing the boiler from successfully igniting.
DIY fix possible
Check that your gas emergency control valve is open and you have credit on your gas meter.If it is freezing outside, check if your white plastic condensate pipe is frozen and thaw it with warm water.Reset the boiler by turning the mode knob to 'RE' and then back to your desired setting.
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