BoilerFaultCodesYour boiler has shut down because there is too much water pressure in the system, which could lead to leaks if not addressed.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Pressure too high, boiler off
What causes this fault?
This fault occurs when the water pressure inside your heating system exceeds the safe operating limit of 3.0 bar. The most common reasons are a filling loop valve being left slightly open or the internal expansion vessel losing its air charge, which prevents it from absorbing the natural expansion of water as it heats up.
This issue often surfaces during the first cold spell of autumn when the heating is turned on for the first time in months, causing the water to expand and reveal a failing expansion vessel.
DIY fix possible
Check that the filling loop valves (silver braided hose) are tightly closedLocate a radiator bleed valve and use a key to release water into a container until the pressure gauge drops to 1.5 barRestart the boiler to see if the code clears
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 P3.0-3.5 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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