Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Cancel purge cycle & If required, reset boiler.
Allow the boiler to start its ignition sequence for DHW.
Isolate Mains Power to appliance as per TOP's P4

Remove actuator from the 3-way valve assembly (see note 1.)
Confirm actuator spindle is in the DHW recessed position (see note 2.)
Note.
1. Due to the diverter valve cartridge being held in by two plastic clips, it is advisable to drain the primary system water from the boiler.
2. Be aware that the spindle may need to be pushed into the recessed position as it relies on the cartridge for this.