BoilerFaultCodesYour boiler has shut down because it has detected an unsafe increase in temperature and has triggered a safety cut-out 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: Safety Thermostat Operated
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, forcing a safety switch to trip and shut the system down. The most common reasons are a lack of water flow caused by a failing pump, a blockage in the pipework, or a buildup of air within the heat exchanger.
This issue often appears when the heating is turned back on after summer, as pump components can seize up during long periods of inactivity.
DIY fix possible
Check that your radiator valves and any zone valves are fully open to allow water to circulate.Ensure your system pressure is topped up to between 1 and 1.5 bar.Allow the boiler to cool down completely, then press and hold the 'Reset' button for five seconds.
Find a Gas Safe engineer
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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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