BoilerFaultCodesYour boiler has shut down because it is detecting dangerously high temperatures in the exhaust flue or a fault with the safety sensor itself.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The temperature measured by the flue gas sensor is too high and is open
What causes this fault?
This fault occurs when the internal safety sensors detect that the exhaust gases are becoming hot enough to potentially damage the boiler's components. The most common reason is a buildup of debris or combustion by-products inside the heat exchanger, which prevents heat from being transferred to your radiators and instead pushes it out through the flue. It can also be triggered by a physical failure or loose connection within the temperature sensor itself.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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