Set Appliance State:

Mains Power Off
Turn hot water tap ON with a flow rate of 3 l/min
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Does the appliance recognise a DHW demand ?
d or H will appear on the display.
Note.
DHW demand is recognised when d or H appear on the display.