BoilerFaultCodesTechnical 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.
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.
Find a Gas Safe engineer
Search the official register →