BoilerFaultCodesTechnical description
Upper water pressure (>2.7b)
What causes this fault?
This fault occurs when the water pressure inside your heating system exceeds a safe operating limit, often because the filling loop valve has been left slightly open or is leaking water into the system. It can also happen if the expansion vessel, which manages pressure changes as water heats up, has failed or lost its air charge. In some cases, a faulty plate heat exchanger may be allowing high-pressure mains water to leak internally into the heating circuit.
This fault is more common in autumn when homeowners top up their boiler pressure for the first time before winter and accidentally overfill the system.
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.