BoilerFaultCodesYour boiler has switched itself off because it has reached a temperature that is too high, often caused by a circulation problem or a blockage.
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 operated or faulty (Section J)
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, triggering a safety switch to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of debris like sludge that blocks the heat exchanger. It can also happen if there is trapped air in the system preventing proper circulation.
This issue often appears when the heating is first turned on after summer, as the internal pump can seize up after long periods of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to zero.Verify that the system pressure is between 1 and 1.5 bar on the pressure gauge.Allow the boiler to cool down, then press the reset button or turn the selector switch to the 'R' position for at least 5 seconds.
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A boiler cover plan would cover faults like Overheat Stat neons flashing — no call-out fees, no surprises.
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Potterton Performa System E is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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