BoilerFaultCodesTechnical description
Fault: Pump/water shortage - Insufficient pressure jump detected when starting the pump
What causes this fault?
This fault occurs when the boiler's internal computer fails to see a small spike in water pressure that should happen the moment the pump begins to spin. The most common reason is that the pressure sensor has become blocked with sludge or debris, though it can also be caused by a failing pump or air trapped within the system. Essentially, the boiler won't fire because it cannot confirm that water is actually moving through the heat exchanger.
This fault is slightly more common in autumn when heating systems are switched back on after a summer of inactivity, as pumps can seize or sludge can settle during the warmer 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.