BoilerFaultCodesYour boiler has shut down because it has reached an unsafe temperature, triggered by a safety sensor that prevents the unit from overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Limit thermostat
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety switch to Cut off the system to prevent damage. The most common reasons are a pump failure that stops water from moving or a blockage in the heat exchanger that restricts flow.
This issue often appears when the heating is first turned on after summer, as the internal pump can seize up after long periods of inactivity.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulate.Ensure your system pressure is topped up to between 1 and 1.5 bar.Turn the boiler off and on again, or press the 'Reset' button to clear the lockout once the system has cooled down.
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 E020 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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