BoilerFaultCodesYour boiler has detected that there is not enough water pressure in the system to operate safely, which has caused it to shut down.
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
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 heat 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 didn't top the pressure back up.
This fault often appears when you turn your heating back on for the first time in autumn, as small leaks or air pockets may have developed during the months of inactivity.
DIY fix possible
Locate the external filling loop, which is usually a flexible silver hose with two small valves underneath or near the boiler.Slowly open both valves to allow water into the system while watching the pressure gauge.Close both valves tightly once the pressure gauge reaches between 1.0 and 1.5 bar.
Find a Gas Safe engineer
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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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