BoilerFaultCodesYour boiler has reached an excessively high temperature and has shut 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: Thermostat operated safety
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, triggering a safety switch to shut the system down. The most common reasons are a pump failure preventing water from moving through the unit, or a internal blockage like air or sludge that is trapping heat in the heat exchanger.
This issue often appears when you first turn the heating back on in autumn, as circulation pumps can seize up if they have been inactive throughout the summer.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulate.Ensure your system pressure is between 1.0 and 1.5 bar on the front gauge.Try resetting the boiler by turning the selector knob to the 'R' position for five seconds.
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E110 — no call-out fees, no surprises.
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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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