Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
DHW temperature set to MAX
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance if required (press reset button for 2 seconds and release).
Does the pump run?
Note.
Do not take sound or vibration as a sign the pump is running.