BoilerFaultCodesTechnical description
Domestic pressure test point
What causes this fault?
This fault occurs when the boiler's safety sensors detect that waste gases are not being effectively cleared from the combustion chamber. The most common reason is a failing internal fan or a blockage in the flue pipe, which prevents the system from ensuring it is safe to ignite.
This fault is more common during periods of high winds, as strong gusts can sometimes obstruct the airflow through the flue and trigger a safety shutdown.
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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