BoilerFaultCodesYour boiler has sensed it is getting too hot, usually because the water inside isn't moving around the system correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat - Normally associated with either poor or lack of primary water circulation. Wait for appliance to cool then reset as described for code 01.
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety sensor to shut the system down. The most common reason is that the water is unable to move through the pipes quickly enough to carry heat away, often due to a broken pump or a blockage in the system. It can also be caused by a build-up of limescale or debris within the heat exchanger that prevents efficient heat transfer.
This fault is more frequent during the first cold spell of autumn, when pumps that have been idle all summer often seize up upon being switched back on.
DIY fix possible
Check that your radiator valves and the boiler isolation valves are fully openEnsure your system water pressure is between 1 and 1.5 bar on the pressure gaugeWait for the boiler to cool down completely, then turn the control knob to the 'Reset' position for a few seconds
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A boiler cover plan would cover faults like 02 — no call-out fees, no surprises.
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