BoilerFaultCodesTechnical description
Debris in flue system, Debris in flue venturi, or the boiler or flue system has developed a 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 dirt or debris in the small tubes inside the boiler, a failing fan that cannot spin fast enough, or a blockage within the external flue pipe.
This fault is more common during the autumn and winter months, as heavy winds or nesting debris can obstruct the flue terminal, and cold temperatures can affect the moving parts of the fan.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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