BoilerFaultCodesWhat the manual says
Manufacturer manualBurner in fault position. The air pressure switch is open at burner start or did not close on reaching the starting load. Check the air pressure switch and the connecting hoses.
What causes this fault?
This fault occurs when the boiler's internal safety sensors fail to detect the necessary airflow required to safely clear exhaust gases. The most common cause is a blockage in the flue or a failure in the fan assembly, which prevents the system from confirming it is safe to ignite the burner.
This fault can be more frequent during periods of high winds, as strong gusts can occasionally interfere with the air pressure balance within the flue system.
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 F5: no call-out fees, no surprise bills.
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