BoilerFaultCodesYour boiler has shut itself down because it has become too hot internally and needs to cool 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: Lockout due to overheat thermostat
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety switch to shut the system down. The most common reasons are a pump failure that stops water from moving or a blockage in the main heat exchanger that prevents heat from transferring correctly.
This fault is more frequent when you first turn the heating back on in Autumn, as pumps can seize up after being inactive over the summer months.
DIY fix possible
Check that your radiator valves are open to allow water to flow.Wait for the boiler to cool down completely.Locate the manual reset button on the control panel and press it firmly.
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 E02 — no call-out fees, no surprises.
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Potterton Powermax HE 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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