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: A flashing indicator shows that the overheat thermostat has cut out.
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety sensor to automatically shut the system down to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of limescale and sludge that restricts flow through the heat exchanger.
This issue often appears when the heating is first turned on after summer, as the internal pump can seize up from lack of use.
DIY fix possible
Turn the boiler main control knob to the 'Reset' position or 'O' for five seconds.Turn the knob back to the 'On' or 'I' position.Check that your radiator valves are open and that the system pressure is between 1 and 1.5 bar.
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