Set Appliance State:

Mains Power Off
Ensure No demands are present
Ensure boiler is cool
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow the boiler to complete its self-check.
If fault code F2 is displayed, reset boiler.
Does the display show the boiler flow temperature?
Note:
If after boiler reset the fault code changes from the original to a different fault code, then CLICK HERE.