BoilerFaultCodesYour boiler has switched itself off because it has detected it is getting too hot, usually caused by the water pressure being too low.
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 has tripped – top-up water until the reset pressure is reached
What causes this fault?
This fault occurs when the internal safety sensor detects that the heat exchanger has become dangerously hot, causing the boiler to shut down to prevent damage. The most common reason is a lack of water circulating through the system, often due to low pressure, a blockage, or a pump failure. If there isn't enough water to carry the heat away to your radiators, the temperature inside the unit rises too quickly.
This issue often surfaces when the heating is first turned on in autumn, as pump components can seize or air locks can develop after being idle during the summer.
DIY fix possible
Check the pressure gauge on the front of the boiler or the digital display.Locate the filling link (usually a blue lever underneath the boiler or a white plastic key).Slowly top up the water pressure until it reaches between 1.0 and 1.5 bar.Press the 'Reset' button on the boiler display to clear the fault.
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