BoilerFaultCodesYour boiler has detected that the water pressure is too low to operate safely and has shut down to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Low water pressure or No water in boiler fault
What causes this fault?
This fault occurs when the system lacks enough water pressure to circulate heat safely, causing the boiler to shut down to protect the heat exchanger. The most common reason is a slow leak somewhere in your radiators or pipework, or simply that the system needs to be topped up after air was bled from the radiators.
This code 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.Open the one or two small valves on the hose until you hear water flowing.Watch the pressure gauge and close the valves when the needle reaches 1.5 bar.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F22 — no call-out fees, no surprises.
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