BoilerFaultCodesYour boiler has stopped working because the water level inside the system has dropped too low and needs topping up.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pressure reading below 0.5 bar on the gauge
What causes this fault?
This fault occurs when the internal water pressure drops below the minimum level required for the boiler to operate safely. The most common reason is a slow leak from a radiator valve or a pipe joint, but it can also happen if you have recently bled your radiators and didn't top up the system afterwards. In some cases, a component inside the boiler like the pressure relief valve may be letting water out of the system gradually.
This fault is frequently seen at the start of autumn when homeowners turn their heating back on for the first time after the summer break.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the one or two small tap handles until you hear water running.Watch the pressure gauge and close the taps firmly once it 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 Low system pressure — 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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