BoilerFaultCodesWhat the manual says
Manufacturer manualAir flow proving fault - that is fan or air pressure switch
What causes this fault?
This fault occurs when the boiler's internal safety checks determine that the fan isn't moving enough air to safely vent exhaust fumes outside. The most common reason is a mechanical failure of the fan motor or a blockage in the small plastic tubes that signal the air pressure to the control board.
This issue can be more common during the first cold snap of autumn, as fan bearings can seize up after sitting idle throughout the summer months.
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.
Avoid the next call-out bill
A cover plan would handle faults like neon 3 not lit: no call-out fees, no surprise bills.
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