BoilerFaultCodesYour boiler has sensed it is getting too hot and has automatically shut down to prevent damage or safety issues.
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 (which cuts off the gas valve)
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches an unsafe temperature, triggering a safety switch to cut the power. The most common reasons are a pump failure preventing water from circulating or a build-up of sludge and debris that blocks the flow of heat away from the burner.
This issue often surfaces when the heating is first turned on after summer, as the internal pump can seize up from lack of use during the warmer months.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulate.Ensure there is enough pressure in the system by checking the gauge is between 1 and 1.5 bar.Gently press the 'Reset' button on the control panel once the boiler has cooled down.
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A boiler cover plan would cover faults like 20 — no call-out fees, no surprises.
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Vokera Linea Max 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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