BoilerFaultCodesYour boiler has shut down because it has detected that the water leaving the unit is getting too hot, which is usually caused by a circulation problem.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Outlet Temperature > 90°C for 5s, the Slave board shuts down
What causes this fault?
This fault occurs when the water inside the boiler heats up too quickly and cannot be moved away into your radiators or hot water cylinder. The most common reason is a failed circulation pump or a blockage in the system, such as a build-up of sludge or limescale, which prevents the heat from being safely dispersed.
This issue is more frequent in autumn when heating systems are switched back on after a long summer break, as pumps can seize up due to inactivity.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Could it be time for a new boiler?
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