BoilerFaultCodesYour boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat thermostat reset button
What causes this fault?
This fault occurs when the water inside the boiler reaches a dangerously high temperature, triggering a safety switch to kill the power. This is usually caused by the pump failing to move water away from the burner quickly enough or a blockage in the heat exchanger restricting flow. It essentially acts as a fuse to prevent the internal components from melting or cracking due to excessive heat.
This issue often surfaces during the first cold snap of autumn when a heating system that has been dormant all summer is suddenly forced to work at maximum capacity.
DIY fix possible
Wait for the boiler to cool down completely (at least 20 minutes).Identify the red reset button on the overheat thermostat (refer to your manual for the exact location on your model).Press the button firmly once to reset the system and attempt to restart the boiler.
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