Set Appliance State:

Ensure boiler is cool
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Boiler reset instructions.
Turn selector switch from ch/dhw position to the off/reset position, after a couple of seconds turn the selector switch back to the ch/dhw position.
Apply a dhw demand, Has the boiler reset ?