Set Appliance State:

Mains Power Off
CH Demand
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance as necessary (hold down both arrow buttons until display changes) and allow the boiler to complete its self-check.
Set the boiler into service mode by holding down the ok button for 5 seconds.
Switch between maximum (100%) and minimum (10%) rate by using the up and down arrows.
To exit service mode press the back button.
Carry out a combustion check at both maximum and minimum rates
as per manufacturer's instructions (refer to Adapt for more guidance).
Is the appliance within CO and CO2 tolerances on both maximum and minimum rate?