Set Appliance State:

CH Demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Is the middle LED on the fascia illuminated, indicating
that the central heating is turned on at the boiler?
If the LED is not illuminated use the switch next to it to turn it on.
If the pump runs after you have turned it on click HERE.
Note:
Ariston show this as a central heating switch / LED but as
this is a system boiler it will stop DHW operation as well.