BoilerFaultCodesYour boiler has stopped working because the water pressure inside the system has dropped too low to allow it to run safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Insufficient system water pressure (min. 0.5 bar) prevents the pump and fan from operating.
What causes this fault?
This fault occurs when the water level inside your central heating system drops below the minimum required for the boiler to operate. The most common reasons are a slow leak from a radiator valve or pipework, or the air pressure inside the expansion vessel needs recharging. In some cases, it can also happen after you have recently bled your radiators, which removes air but also lowers the overall system pressure.
This issue is frequently seen in autumn when homeowners turn their heating back on for the first time after summer, revealing pressure drops that occurred while the system was idle.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the one or two small valves on the ends of the pipe until you hear water flowing.Watch the pressure gauge and close the valves tightly once the needle reaches between 1 and 1.5 bar.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Low-pressure — no call-out fees, no surprises.
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