BoilerFaultCodesWhat the manual says
Manufacturer manualN/A
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water is not moving through the heat exchanger as quickly or efficiently as it should. The most common reason is a mechanical failure of the circulation pump or a buildup of debris that has physically jammed the pump's internal components. In some cases, it may also be triggered by a communication error where the main control board is unable to tell the pump to spin.
This fault is more frequent in autumn when the heating is turned back on after a long summer break, as pumps can often seize up during months of inactivity.
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 A2: no call-out fees, no surprise bills.
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