BoilerFaultCodesYour boiler has detected that there is not enough water pressure in the system to operate safely, causing 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 level
What causes this fault?
This fault occurs when the internal sensors detect that the system's water pressure has dropped below the minimum level required for safe operation. The most common reason is a slow leak somewhere in your radiators or pipework, though it can also happen if you have recently bled your radiators without topping the pressure back up.
This issue often surfaces in autumn when homeowners turn their heating back on for the first time, as the change in temperature can highlight minor leaks or pressure loss during the summer.
DIY fix possible
Check the pressure gauge on the boiler or pipeworkLocate the external filling loop (braided silver hose)Slowly open the valves to top up the water until the pressure is between 1.0 and 1.5 barEnsure valves are closed tightly and reset the boiler
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 14-15 — no call-out fees, no surprises.
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Remeha Gas 350 is discontinued — time for a new one?
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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