BoilerFaultCodesYour boiler has detected that the water pressure in the system is too low to run safely and has stopped working as a result.
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 pressure / system pressure is low
What causes this fault?
This fault occurs when the internal sensors detect that there isn't enough water circulating through the pipes and radiators to operate safely. The most common reason is a slow leak somewhere in the system or because the radiators were recently bled, which removes water and lowers the overall pressure. Over time, the pressure can also drop if the expansion vessel—a part that manages water volume—is failing to do its job.
This issue is frequently seen at the start of autumn when homeowners turn their heating back on for the first time after summer and discover the pressure has gradually drifted down.
DIY fix possible
Locate the two blue-handled filling loop valves underneath the boiler.Turn both valves slowly to allow water into the system while watching the pressure gauge.Close both valves tightly once the needle reaches between 1.0 and 1.5 bar.
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