Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
CH temperature control set to MAX
Ensure pump is at maximum speed setting
Remove Pump Vent Screw as necessary
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance if it is in lockout.
Does the pump run satisfactorily?
Note:
Do not take vibration as an indication of pump running, if pump vent plug is removed to observe pump shaft turning, then care should be taken that water does not drip onto the boiler electrics.