Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Remove connector from Aqua sensor and make safe
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Measure voltage across the black (2)
and red (3) leads on the connected plug X2.
Is approximately 5 vdc now measured?