BoilerFaultCodesTechnical description
Pump / Water pressure sensor fault
What causes this fault?
This fault occurs when the boiler's control board fails to detect a small surge in water pressure that should happen every time the internal pump starts up. The most common reason is that the pressure sensor has become blocked with sludge or has failed, but it can also be caused by a sticking pump or a loss of air in the expansion vessel. Because the boiler cannot confirm that water is moving through the system, it shuts down as a safety precaution to prevent overheating.
This fault is more frequent in autumn when the heating is turned back on after a long summer break, as the pump can seize or 'stick' due to several months of inactivity.
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.