BoilerFaultCodesYour boiler has lost water pressure and has shut itself down to prevent damage to the internal components.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Loss of pressure in heating system
What causes this fault?
This fault occurs when the water level inside your central heating system drops below the minimum safe threshold required for operation. The most common reasons are a slow leak from a radiator valve or pipework, or a failing internal component like the expansion vessel which helps manage pressure changes.
This issue is frequently seen in autumn when the heating is turned back on after summer, as the sudden heat can stress weakened seals or joints.
DIY fix possible
Locate the filling loop (usually a silver flexible hose) underneath or near the boilerSlowly open the tap or taps on the filling loop until you hear water movingWatch the pressure gauge and close the taps firmly once it reaches 1.5 bar
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 P0.1-0.4 bar — no call-out fees, no surprises.
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Potterton Powermax HE 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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