BoilerFaultCodesYour boiler has stopped working because it cannot detect any water moving through the system to keep it from overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner fault: Flow switch has not responded
What causes this fault?
This fault occurs when the boiler's internal sensors fail to detect water circulating through the heat exchanger after the pump has started. The most common cause is a seized pump or a blockage in the pipework that prevents the flow switch from physically moving into the 'on' position. If the boiler cannot confirm that water is moving to carry heat away, it shuts down immediately to prevent the unit from melting or exploding.
This issue is more frequent in autumn when the heating is turned on for the first time after summer, as internal pump components can seize up during long periods of inactivity.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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