BoilerFaultCodesWhat the manual says
Manufacturer manualWater pressure too high: Water pressure > 2.8 bar
What causes this fault?
This fault occurs when the internal water pressure exceeds safe operating limits, often because the filling loop used to top up the system has been left slightly open or is leaking. It can also be caused by a failure in the expansion vessel, which is the part responsible for managing the natural pressure increase that happens when water heats up.
This issue often appears at the start of autumn when homeowners turn their heating back on after a long break, causing the water to expand and reveal underlying pressure problems.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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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