BoilerFaultCodesYour boiler has stopped heating because it cannot detect any water moving through the system to keep it safe.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow switch terminals are left disconnected
What causes this fault?
This fault occurs when the boiler's internal safety sensor cannot detect water circulating through the heat exchanger. The most common reason is a failed central heating pump or a blockage in the pipework that prevents the water from moving fast enough to trigger the flow switch. Without this movement, the boiler shuts down to prevent the internal components from overheating and sustaining damage.
This issue often surfaces in autumn when the heating is turned back on for the first time, as pump internal parts can seize up after being idle during the summer months.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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