BoilerFaultCodesYour boiler has detected an issue with how it is venting exhaust gases, which has caused it to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Indicates that the flue or flue terminal is blocked or obstructed in some way, or that there is an internal fault.
What causes this fault?
This fault occurs when the boiler's safety sensors detect that harmful exhaust gases are not being cleared from the system effectively. The most common reasons are a buildup of debris in the fan or air tubes, or a mechanical failure in the switch that confirms the fan is spinning fast enough to operate safely.
This issue is frequently seen during periods of high winds, which can create back-pressure in the flue, or in autumn when falling leaves can physically block the external terminal.
DIY fix possible
Check the external flue pipe on the outside wall for any visual obstructions like bird nests, leaves, or debris.Ensure there is nothing leaning against or covering the flue terminal.Turn the selector switch to the reset position for five seconds and then back to the required setting.
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