BoilerFaultCodesYour boiler has automatically shut itself down because it became too hot, acting as a safety measure to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The boiler is fitted with a safety thermostat to protect against overheating of the water. If this thermostat operates the boiler will lockout and fail to re-light.
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches a dangerously high temperature, triggering a safety switch to cut the power. The most common reasons are a failed pump that isn't moving water around the system quickly enough or a blockage in the pipework caused by a build-up of sludge. It can also happen if the external controls fail to tell the boiler to turn off once the house is warm.
This issue often surfaces during the first cold spell of autumn when the heating system is turned back on after being idle all summer, which can cause internal parts like the pump to seize.
DIY fix possible
Wait for the boiler to cool down completely (at least 30 minutes).Locate the reset button, usually found under the front of the boiler casing.Press the button firmly to reset the thermostat; the boiler should then attempt to relight.
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A boiler cover plan would cover faults like Overheat Limit Thermostat — no call-out fees, no surprises.
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