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:

Allow boiler to complete self-check then enter standby.
Turn hot water tap on with a flow rate of 2.8 litres a minute.
Does the pump and fan start to run with a DHW demand?