BoilerFaultCodesTechnical description
Burner blocked
What causes this fault?
This fault occurs when the boiler's internal sensors detect that exhaust gases cannot exit the building or fresh air cannot enter the system properly. It is usually caused by a heavy buildup of debris within the heat exchanger or a blockage in the flue pipe, which prevents the burner from firing safely. In some cases, a blocked condensate trap can also cause water to back up, effectively choking the combustion process.
This fault can be more frequent in autumn or during high winds, as fallen leaves or debris can 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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