BoilerFaultCodesYour boiler has stopped working because either the water pressure is too low or the pump that circulates water is struggling to move it around.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault on Pump or Low System Pressure
What causes this fault?
This fault occurs when the boiler detects that water is not circulating through the system correctly or there isn't enough pressure to operate safely. It is usually caused by a drop in water pressure due to a leak, or the internal pump becoming stuck or failing after years of use. If the system is full of water but the fault remains, it often means the pump can no longer push water around your radiators.
This issue is frequently seen in autumn when the heating is turned back on for the first time, as pump components can seize up after sitting idle over the summer.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is below 1 bar, use the external filling loop to top up the water levels.Ensure all radiator valves are open and that the system has been bled of any trapped air.
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A boiler cover plan would cover faults like 23 — no call-out fees, no surprises.
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