BoilerFaultCodesYour boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety switch-off – low water pressure in boiler
What causes this fault?
This fault occurs when the water pressure inside your heating system drops below the minimum level required for the boiler to fire up safely. The most common reason is a slow leak from a radiator valve or pipework, though it can also happen if you have recently bled your radiators and haven't topped the pressure back up.
This fault often appears in autumn when homeowners turn their heating back on for the first time, as small leaks may have developed or radiators may have been bled during the summer break.
DIY fix possible
Locate the filling loop (a flexible silver hose) underneath or near the boiler.Slowly open the one or two taps on the hose until you hear water flowing.Watch the pressure gauge and close the taps once the needle reaches between 1.0 and 1.5 bar.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F.22 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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