BoilerFaultCodesYour boiler has detected that the water pressure inside the system is too high, which can cause safety valves to leak or the unit to shut down.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: High pressure
What causes this fault?
This fault occurs when there is too much water in your heating system, placing excessive strain on internal components. The most common reason is that the filling loop has been left slightly open after topping up the pressure, though it can also happen if a component like the expansion vessel has failed and can no longer regulate water volume as it heats up.
This issue often appears at the start of autumn when homeowners bleed their radiators and accidentally overfill the system while preparing for the colder months.
DIY fix possible
Locate a radiator bleed valve and use a key to release a small amount of water into a jug.Monitor the pressure gauge on the boiler until it returns to between 1 and 1.5 bar.Ensure the external filling loop valves are tightly closed to prevent more water entering the system.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like P8 — no call-out fees, no surprises.
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Worcester Bosch WR325 RSF 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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