Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance as necessary and allow the boiler to complete its self check.
Set the boiler into service mode by holding down the spanner and eco buttons for approx 5 seconds.
Switch between maximum and minimum rate by using the up and down arrows.
To exit service mode press the OK 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?