Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Selector Switch to Hot Water and Heating
Appliance CH thermostat set to MAX
Attach a temperature clamp to the flow pipe as indicated by the red arrow
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow boiler and system to heat, whilst monitoring the temperature on the performance tester.
The boiler should heat to a maximum temperature of approximately 70-75°C.
The boiler should reach this temperature without cutting out on overheat.
It should also shut the burner down when the maximum temperature is reached.