BoilerFaultCodesYour boiler has shut down because the internal exhaust gases are getting too hot, which is usually caused by a circulation problem or a buildup of debris inside the main heating component.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue overheat – check combustion and flue temperature vs. return temperature – the flue temperature should be no more than 10C above return temperature. Possible heat exchanger fault.
What causes this fault?
This fault occurs when the internal temperature of the exhaust gases becomes dangerously high, triggering a safety shutdown to protect the appliance. The most common reason is that heat isn't being transferred effectively into your radiators, often due to a buildup of dirt or debris inside the main heat exchanger. It can also be caused by a lack of proper water flow through the boiler, which prevents the system from cooling itself down while firing.
This fault is more common in the autumn or winter when the heating is first turned back on, as stagnant sludge in the system can shift and block the narrow channels of the heat exchanger.
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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A boiler cover plan would cover faults like E07 — no call-out fees, no surprises.
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