BoilerFaultCodesYour boiler has sensed that it is getting dangerously hot and has shut itself down to prevent damage or overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety temperature limiter in CH flow or flue gas temperature limiter has operated
What causes this fault?
This fault occurs when the internal sensors detect that the water or exhaust gases have reached a dangerously high temperature. The most common reason is a lack of water circulation, often caused by a failed internal pump or a blockage in the system pipework that prevents heat from being carried away from the burner. It can also happen if there is an air lock in the heat exchanger or if the sensors themselves have developed a fault.
This fault often appears during the first cold spell of autumn when the heating is turned back on after months of inactivity, as internal pumps are prone to seizing during the summer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like E9 — no call-out fees, no surprises.
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