BoilerFaultCodesYour boiler has stopped working because the water pressure is too low for it 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: Insufficient water pressure. Check pressure gauge reading, if low restore pressure (see 6.3.4) then re-set as described in code 01. Re-set as described for code 01.
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 somewhere in your central heating system, though it can also happen if you have recently bled your radiators and haven't topped the pressure back up.
This fault is frequent in autumn when homeowners turn their heating back on for the first time after summer, often revealing pressure drops that occurred while the system was idle.
DIY fix possible
Locate the filling loop (the flexible silver hose) under the boiler.Slowly open the valve or valves on the loop until you hear water moving.Watch the pressure gauge until it reaches between 1 and 1.5 bar, then close the valves completely.Turn the control dial to the 'Reset' position and then back to your original setting.
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A boiler cover plan would cover faults like 04 — 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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