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: Low water pressure (below 0.5 bar)
What causes this fault?
This fault occurs when the water level inside your central heating system drops below the minimum required for the boiler to heat up safely. The most common reasons are a small leak in your pipework or radiators, or because the expansion vessel inside the boiler has lost its air charge and can no longer regulate pressure.
This code is frequently seen when homeowners turn their heating back on for the first time in autumn, as the system settles and reveals pressure losses that occurred over the summer.
DIY fix possible
Locate the filling loop (a flexible silver hose) usually found underneath or near the boiler.Slowly open the valve(s) on the filling loop to allow water into the system.Watch the pressure gauge and close the valves tightly once the needle reaches between 1 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 P19 — 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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