Set Appliance State:

Mains Power Off
CH Demand
CH temperature control set to maximum
Ensure appliance is cool, this can be achieved by running a hot tap with the appliance switched off
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Appliance On/Off control set to ON position.
Reset lockout as necessary.
Allow the fan to run and the ignition sequence to commence.
With a CH demand does the pump run and does the burner ignite?
Note:
Do not take sound or vibration as sign of pump running.
If vent plug is removed to observe pump shaft then care should be taken that water does not drip on to the control box.