Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Plastic cover of Diverter valve removed
All hot taps closed

Observation:

Turn Hot Water Tap On
Observe the action of the Diverter valve plunger on the micro-switches as a hot tap is opened.
Does the Diverter Valve plunger push out and operate the micro-switches fully?