BoilerFaultCodesYour boiler has detected that there is not enough water pressure or flow to operate safely, which is preventing your heating and hot water from working.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Failed low water – pressure switch or pump, possible issue with pump, incorrect system pressure or the low water switch pressure needs replacing
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water is not circulating correctly or the pressure has dropped too low to operate safely. The most common reason is a simple loss of water pressure in the central heating system, but it can also be caused by a mechanical failure of the pump or a faulty sensor that is incorrectly reporting low pressure.
This issue often surfaces when the heating is turned back on for autumn, as stagnant pumps can seize or system pressure may have dropped during a summer of inactivity.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.If the pressure is too low, use the external filling loop to top up the system with water.Ensure all radiator valves are open and bleed any air from the radiators.Turn the boiler off and back on again to reset the fault.
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A boiler cover plan would cover faults like 28 — no call-out fees, no surprises.
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Ravenheat CSI 120 is discontinued — time for a new one?
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