BoilerFaultCodesTechnical description
Primary water circulation fault
What causes this fault?
This fault occurs when water is unable to flow through the boiler quickly enough, leading to a sudden rise in temperature. The most common reason is a failed internal pump or a blockage in the system caused by a buildup of sludge and debris. It can also happen if there is an air lock or if the radiator valves are all turned off, preventing the heat from escaping.
This fault is frequently seen at the start of autumn when heating systems are turned back on after being idle all summer, which can cause internal pump parts 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.
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