Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Preheat OFF
Unclip and remove head from diverter valve and place in a safe position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Inspect the diverter head, ensure that the small brass pin of the head is fully retracted during a hot water demand.