BoilerFaultCodesYour boiler has stopped working because the water pressure is too low for the system to run safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water Pressure Switch Not Operated / primary water pressure is less than 0.5 bar
What causes this fault?
This fault occurs when the pressure of the water circulating inside your heating system drops below a safe working level, usually because of a small leak or after you have recently bled your radiators. Without enough water pressure, the boiler cannot safely move heat around your home, so it shuts down to prevent the internal components from overheating. While often fixed by topping up the system, persistent pressure loss may indicate a failing part like the expansion vessel.
This code is frequently seen in autumn when homeowners turn their heating back on for the first time after summer, as natural pressure loss often occurs during periods of inactivity.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) under or near the boiler.Slowly open the one or two taps/levers on the filling loop until you hear water entering.Watch the pressure gauge and close the taps once the 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 E119 — 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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