BoilerFaultCodesYour boiler has shut down because it has detected it is getting too hot, likely due to a lack of water flow or a sensor failure.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Permanent fault. Maximum safe temperature value reached, safety thermostat open-circuited, no circulation, sensor not or badly connected, bad connection or sensor fault.
What causes this fault?
This fault occurs when the boiler's internal water temperature exceeds a safe limit, causing the system to shut down to prevent damage. The most common reasons are a lack of water circulation caused by a failed pump, a blockage in the heat exchanger, or a faulty sensor providing an incorrect temperature reading.
This issue often surfaces when the heating is first turned on in autumn, as internal pumps can seize up after being idle throughout the summer.
DIY fix possible
Check that the boiler pressure is between 1.0 and 1.5 bar on the gaugeEnsure all radiator valves are fully open to allow water circulationPerform a reset by turning the selector knob to the 'R' position for five seconds
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E.04 – .08 — 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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