BoilerFaultCodesTechnical description
Overheat safety cutoff device may need resetting
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches a dangerously high temperature, triggering a safety switch to cut off the burner. The most common reason is a failure in the circulation pump or a blockage in the pipes, which prevents the heat from being carried away to your radiators. It can also be caused by air trapped in the system or a faulty sensor incorrectly reading the temperature.
This issue often surfaces at the start of autumn when the heating is turned back on after a long summer break, as pump components can seize up during 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.