Set Appliance State:

Mains Power Off
CH Demand
Allow the heating system to warm up until the burner cuts off
Set the boiler thermostat for heating at 50°C
User display control set to HW and CH
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

After the burner has extinguished increase the boilers heating thermostat to 60°C
When the burner has extinguished observe the boiler, after approximately 3 minutes the boiler should re fire.
Note:
To reduce the time it takes for the boiler to reach temperature some radiators can be turned off.