Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect the flow switch connector from the flow switch
Disconnect connector X6 from the control PCB
Disconnect connector X6 from the control PCB
Measurement:
Measure the resistance between pin 5 (white) and pin 6 (blue) wires at the disconnected plug.
Expected resistance open circuit.
Expected resistance open circuit.
Isolate as per TOPs P4
and refit as necessary