BoilerFaultCodesYour boiler has automatically shut down because the water inside the system has become too hot.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: High water temperature limit
What causes this fault?
This fault occurs when the internal sensors detect that the water temperature has exceeded safe limits, triggering a safety shutdown to prevent damage. The most common reason is that water isn't moving through the unit quickly enough, often due to a pump failure, a blockage in the pipework, or a build-up of sludge. In some cases, the sensor itself may have developed a fault and is incorrectly reporting that the system is overheating.
This issue often surfaces during the first cold spell of autumn when the heating system is turned back on after being idle all summer, which can cause internal pump components to seize.
DIY fix possible
Check that all radiator valves (TRVs) are fully open to allow water to circulate.Verify that your system pressure is between 1.0 and 1.5 bar.Press the reset button on the boiler control panel once the system has cooled down.
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