BoilerFaultCodesTechnical description
No pressure rise was detected on turning on the pump | Water pressure sensor or/and pump defective Air in the heating system, quick bleeder defective Too little water in appliance; check adjustable by-pass; connect external expansion vessel to return
What causes this fault?
This fault occurs when the boiler's internal computer fails to detect a rise in water pressure after it tells the pump to start spinning. The most common reason is that the pressure sensor has become blocked with sludge or has failed, but it can also happen if the pump itself has seized or if there is not enough water in the system to move.
This fault is more frequent in autumn when the heating is turned on for the first time after summer, as the pump can seize or 'stick' after long periods 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.