BoilerFaultCodesYour boiler has detected that the water pressure is too low to operate safely, which is usually caused by a leak or air trapped in the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Insufficient water pressure, Air in boiler. Pressure in the boiler is low.
What causes this fault?
This fault occurs when the internal sensors detect that the water level inside your central heating system has dropped below a safe threshold. The most common reason is a slow leak from a pipe or radiator, though sometimes the pressure drops simply because air has escaped through the system's vent.
This issue is frequently seen in autumn when the heating is turned on for the first time after summer, as stagnant air bubbles move through the system or old seals begin to weep.
DIY fix possible
Locate the filling loop (a flexible silver hose) underneath the boiler.Slowly open the one or two taps on the hose until you hear water flowing.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 04 — no call-out fees, no surprises.
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Vokera Syntesi E 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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