BoilerFaultCodesYour boiler has detected too much water pressure in the system, which can cause internal damage or 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: Exceeded maximum pressure
What causes this fault?
This fault occurs when there is too much water in your central heating system, which puts excessive strain on internal components. The most common reasons are a filling loop valve being left slightly open or a failure in the expansion vessel, which is the part responsible for managing water pressure as it heats up.
This fault is slightly more common in autumn when homeowners top up their system pressure before turning the heating on for the first time.
DIY fix possible
Check that the internal or external filling loop valves are tightly closed.Locate a radiator and use a bleed key to release water into a container until the pressure gauge on the boiler drops back into the green zone (usually 1.0 to 1.5 bar).Monitor the pressure gauge to ensure it stays stable after the boiler is restarted.
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A boiler cover plan would cover faults like 111 — no call-out fees, no surprises.
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