Set Appliance State:

Mains Power Off
CH Demand
User display control set to HW and CH
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Observe the boiler does it react to the heating demand?
Note:
It may take up to 3 minutes to react due to a built in delay function, this time can be shortened by turning the mains power to the appliance off and then on again.