BoilerFaultCodesTechnical description
Pump Fault or Primary Circulation Problem (i. If within 15 seconds of the burner lighting the boiler temperature has not changed by 1°. ii. If within 10 minutes of the burner lighting the boiler temperature twice exceeds the selected temperature by 30°.)
What causes this fault?
This fault occurs when water is not moving through the boiler fast enough to take the heat away from the internal heat exchanger. The most common reason is a failed internal pump or a blockage in the system pipes, which causes the temperature to spike too quickly and triggers a safety shutdown. It can also be caused by a faulty sensor giving the boiler incorrect information about how hot the water actually is.
This fault is more frequent during the first cold snap of autumn when heating systems are turned back on after being idle all summer, which can cause internal pump components to seize.
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.