BoilerFaultCodesYour boiler has sensed it is getting too hot and has shut itself down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat cut-off
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety sensor to cut off the burner. The most common reasons are a pump failure that prevents hot water from moving away from the heat exchanger, or a buildup of debris and sludge that creates a blockage in the system. It can also be caused by a simple air pocket trapped within the pipework following a recent repair.
This issue often surfaces in autumn when the central heating is switched back on for the first time, as pumps can become seized after sitting idle during the summer months.
DIY fix possible
Check that your radiator valves are open to allow water to circulate.Ensure there is enough water pressure in the system by checking the pressure gauge (usually between 1 and 1.5 bar).Press and hold the reset button for five seconds once the boiler has cooled down.
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 Central heating and domestic hot water demand indicators BOTH FLASHING SLOW (once per second) — no call-out fees, no surprises.
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Worcester Bosch 24/28CDi II RSF 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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