BoilerFaultCodesYour boiler has switched itself off because it has reached a temperature that is too high and needs to cool down and be checked.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat lockout
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 to prevent damage. It is usually caused by a lack of water flow, often due to a pump failure or a blockage in the internal pipework. In some cases, a faulty sensor might incorrectly signal that the boiler is overheating even when the temperature is safe.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 E03 — 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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