BoilerFaultCodesTechnical description
Illuminates if the circulating pump is faulty or the system pressure drops below the minimum requirement.
What causes this fault?
This fault occurs when the boiler detects that there is either insufficient water volume to operate safely or that the water isn't being pushed through the pipes. The most common reason is a simple drop in system pressure due to a small leak or recently bled radiators, but it can also be caused by a mechanical failure of the internal pump. Without enough pressure or flow, the boiler shuts down to prevent the heat exchanger from overheating.
This issue often surfaces in autumn when the heating is turned on for the first time after summer, as the pump can seize during long periods 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.