BoilerFaultCodesYour boiler has switched itself off because the water pressure is too low for it 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: Low water pressure/No water in system.
What causes this fault?
This fault occurs when the system loses the physical water pressure required to circulate heat around your home. The most common reason is a small leak in the radiator network or the boiler's internal components, though it can also happen if you have recently bled your radiators without topping the water back up.
This fault often appears when you turn your heating back on for the first time in autumn, as the system settles after being idle for several months.
DIY fix possible
Locate the filling loop (usually a silver braided hose with small valves) underneath the boiler.Slowly open the valves until you hear water moving and watch the pressure gauge.Close both valves tightly once the pressure needle reaches between 1.0 and 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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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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