Set Appliance State:

Mains Power Off
CH Demand
CH temperature control to max
On-Off switch ON
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler to reach MAX CH temperature (75°C).
Choose from the following:
Boiler goes to overheat lockout (F76 / F20 fault code)
Boiler reaches temperature and shuts down without fault

Note:
To speed up the heating of the system, reduce the system circuit by shutting off some radiators.