BoilerFaultCodesTechnical description
Flue and / or air supply duct is blocked
What causes this fault?
This fault occurs when the boiler's internal sensors detect that it cannot safely pull in fresh air or expel exhaust gases. The most common reasons include an external blockage in the flue pipe, such as a bird's nest or debris, or a mechanical failure of the fan that prevents air from moving through the system.
This fault can occur more frequently during autumn or high winds, as fallen leaves or wind-blown debris are more likely to obstruct the external flue terminal.
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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