Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector CN9 from the PCB

Measurement:

Measure the resistance between pin 7 (purple)
and pin 8 (purple) on connector CN9.
Expected resistance open circuit.
Run a hot tap at 2 litres/min and repeat the above test.
Expected resistance short circuit.