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 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, watching the temperature on the Performance Tester.
The temperature should heat to approx. 70-75°C
The boiler should reach this temperature without cutting out on the overheat.
It should then either shut the burner down or modulate when the temperature is reached.