Set Appliance State:

Mains Power Off
Gas Off
Mode Selector Switch in off position.
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Turn on HW tap.
Does DHW Flow Switch and fulcrum arm operate DHW Flow Microswitch?
Turn off HW tap.
Does DHW Flow Switch and fulcrum arm release DHW Flow Microswitch?