BoilerFaultCodesYour boiler has overheated because the gases leaving the flue have become too hot, causing a safety switch to trigger and shut down the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue 'stat reset button (behind sealing panel)
What causes this fault?
This fault occurs when the internal safety sensors detect that the exhaust gases have reached a dangerously high temperature, triggering a shutdown to protect the boiler's internal components. The most common reason is a buildup of limescale or debris inside the heat exchanger, which prevents heat from being transferred to your water and instead sends it out through the flue. It can also be caused by a faulty flue thermostat or a blockage in the system's airflow.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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