BoilerFaultCodesYour boiler has become too hot and has shut itself down as a safety precaution 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: Boiler overheat tripped
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches an unsafe temperature, triggering a safety sensor to cut the power. The most common reasons are a pump failure preventing water from moving through the system or a blockage such as lime scale or sludge restricting the flow. Sometimes, the overheat thermostat itself has simply become faulty and is sending a false signal to the control board.
This fault is more common in winter when the heating is first turned on after a long summer break, as circulating pumps can often seize or stick during months of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to off or zeroEnsure your system water pressure is between 1 and 1.5 bar on the pressure gaugeTurn the selector switch to the reset position for five seconds and then back to your desired setting
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 2 Red Flashes — no call-out fees, no surprises.
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Baxi MainEco 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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