BoilerFaultCodesWhat the manual says
Manufacturer manualWater pressure too high. The system pressure is too high.
What causes this fault?
This fault occurs when the water pressure inside your heating system exceeds the safe limit, often because the filling loop used to top up the system has been left slightly open or is leaking. It can also happen if the expansion vessel, which manages heat-related pressure changes, has failed or if the system has been significantly overfilled during recent maintenance.
This fault is more common in autumn when homeowners top up their system pressure ahead of the heating season and accidentally add too much water.
DIY fix possible
Check that the internal or external filling loop valves are fully closed.Bleed water from a radiator using a bleed key to reduce the system pressure.Monitor the pressure gauge on the boiler screen to ensure it returns to between 1.0 and 1.5 bar.
Avoid the next call-out bill
A cover plan would handle faults like S.41: no call-out fees, no surprise bills.
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