BoilerFaultCodesYour boiler has switched itself off because it has reached an unsafe temperature, likely due to a circulation issue or a component failure.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat cut off device tripped or thermostat, overheat cut off device faulty
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, triggering a safety switch to shut the system down to prevent damage. The most common reason is that water isn't moving through the unit quickly enough, often due to a failed internal pump or a blockage in the pipework. In some cases, the safety sensor itself may have developed a fault and is reporting an 'overheat' incorrectly.
This issue often surfaces during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause the internal pump to seize.
DIY fix possible
Check that all radiator valves are fully openEnsure the system pressure is between 1 and 1.5 barPress the reset button on the control panel once the boiler has cooled down
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