Set Appliance State:

Mains Power Off
DHW Demand
CH Temperature control set to MAX
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to carry out its self check.
Does the boiler respond to a DHW demand and is DHW operation satisfactory?
Note:
Boiler does not differentiate between DHW and CH demand so radiator symbol will still be shown for DHW demand.