Set Appliance State:

Mains Power Off
CH Demand
CH temperature control to max
ON/OFF switch ON
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Is the water pump running?
Note:
Do not take sound or vibration as an indication of the pump running.
If the pump vent plug is removed or loosened (depending on type of pump)
care must be taken to ensure water does not cause damage.