BoilerFaultCodesYour boiler has stopped working because the water pressure is too low for the system 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 water pressure in the system (less than 0.5 bar)
What causes this fault?
This fault occurs when the internal sensors detect that the water level has dropped below the minimum safe operating limit. The most common reason is a slow leak from a radiator valve or joint, though pressure can also drop if you have recently bled your radiators without topping the system back up.
This issue is more frequent in autumn when homeowners turn their heating back on after the summer and discover pressure has gradually bled away over several months.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.Slowly open the one or two taps/valves until you hear water entering the system.Watch the pressure gauge and close the taps firmly once 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 F0 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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