Set Appliance State:

Mains Power Off
CH Demand
ON/OFF Switch ON
Summer/Winter button set to Winter
CH Temperature selector to maximum
DHW Temperature selector to minimum
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to ignite and run in central heating mode and monitor the operation of the boiler / system and system pressure.
Does the heating system start to heat correctly?
Does the system pressure remain stable as the system heats?