BoilerFaultCodesYour boiler has detected a problem with how it releases exhaust gases or a failure to light the burner correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The flue or flue terminal is blocked or obstructed in some way, or there is an internal fault. (Burner On: Off, Flame Failure: Fast Flashing, Power On: On)
What causes this fault?
This fault occurs when the boiler's internal safety sensors detect that either the burner has failed to light or that waste gases are not being safely cleared through the flue pipe. The most common reason is a component failure, such as a faulty fan or an air pressure switch that cannot confirm it is safe to proceed with the ignition sequence.
This fault can be more common during periods of high winds, as strong gusts can sometimes obstruct the terminal or interfere with the pressure balance required for the boiler to operate.
DIY fix possible
Check the outside flue pipe to ensure it isn't blocked by debris, bird nests, or snowTurn the selector switch to the 'Reset' position for five seconds, then back to the 'On' positionCheck that your gas credit hasn't run out or that the gas emergency control valve is open
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