BoilerFaultCodesYour boiler has switched itself off because it has reached an unsafe temperature or it has detected a faulty component in its safety system.
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, causing a safety switch to trip and shut the system down to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of debris that blocks the flow, but it can also be caused by a sensor that has simply become faulty over time.
This issue is more frequent when you first switch your heating on for the winter, as pumps can seize up after being inactive throughout the summer months.
DIY fix possible
Wait for the boiler to cool down completely (at least 20-30 minutes).Locate the manual reset button, which is usually found under the boiler casing.Press the reset button once; if the neon light comes back on and stays on, the system has reset.
Find a Gas Safe engineer
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