Set Appliance State:

Turn hot water tap ON with a flow rate of 4 l/min
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance if required.
(press and hold the reset button for 4 seconds then release)
Does the boiler recognise the DHW demand?
Does the fan run if the DHW demand is recognised?