BoilerFaultCodesTechnical description
High water pressure due to excessive water pressure or safety valve error
What causes this fault?
This fault occurs when the water pressure inside your heating system exceeds the safe operating limit. The most common reason is that the filling loop was left slightly open after topping up the system, or the internal expansion vessel has lost its air charge and can no longer balance the pressure changes as the water heats up. In some cases, a leaking internal component might be allowing fresh mains water to constantly enter the system.
This fault often appears when you first turn the heating back on for autumn, as the expansion of heating cold water can push an already high-pressure system over the safety limit.
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.