BoilerFaultCodesYour boiler has detected that the water pressure is too low to operate safely and has shut down to prevent damage.
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 fault
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 fire up. The most common reason is a small leak in the pipework or radiators, though it can also happen if you have recently bled your radiators without topping the water back up.
This fault is more common in autumn and winter when the heating is first turned on, as the increased demand can expose small leaks or reveal a loss of pressure that occurred while the system was idle.
DIY fix possible
Locate the filling loop (usually a flexible silver hose) underneath or near the boiler.Slowly open the one or two taps/valves on the filling loop while watching the pressure gauge.Close the valves firmly once the pressure gauge needle reaches between 1.0 and 1.5 bar.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like AL41 — 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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