BoilerFaultCodesYour boiler has switched itself off because it has reached an unsafe temperature and needs to be cooled down and reset.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety Temperature Limiter (overheat) operates. Turn temperature control to '0' and then back to original position.
What causes this fault?
This fault occurs when the water inside the heat exchanger becomes too hot, triggering a safety switch to prevent damage. The most common reasons are a pump failure that stops water from moving around the system or a build-up of sludge that creates a blockage.
This issue often appears when the heating is first turned on after summer, as the pump can seize up after long periods of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to zero.Turn the boiler temperature control knob to the 'O' position.Wait a few minutes for the unit to cool, then turn the knob back to your desired temperature setting to reset the fault.
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