Set Appliance State:

Mains Power Off
Gas Off
Turn Hot Water Tap On
Purge Switch in NORMAL position
HW Switch in ON position
CH Switch in OFF position
HW Potentiometer set to maximum
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Does the HW Pump operate?
Note:
Do not take noise or vibration as a sign of pump operation.