BoilerFaultCodesYour boiler has likely overheated because the water is not circulating properly or a sensor has detected a temperature that is too high.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: High limit protection – flow temperature sensor not active, incorrectly located or no system circulation. Check the position of the flow sensor or check pump and radiator valves
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature limit, causing the system to shut down for safety. It is most commonly caused by a failed circulation pump or a blockage in the pipework that prevents heat from being moved away from the heat exchanger. In some cases, it can also be triggered by a faulty sensor that is incorrectly reporting the temperature.
This issue is more frequent in autumn when heating is turned back on after a long summer break, as internal pump components often seize during periods of inactivity.
DIY fix possible
Check that your radiator valves are openEnsure there is enough water pressure on the gauge (usually 1.0 to 1.5 bar)Try resetting the boiler using the 'R' button once it has cooled down
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A boiler cover plan would cover faults like A03 — no call-out fees, no surprises.
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Ferroli Modena HE 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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