Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
Turn Hot Water Tap On
Gain access to PCB (use Insulation Mat as required)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Reset lockout as necessary.
Measure the AC voltage between pins 4 and 7 on the 7 wire connector on the PCB.
Expect mains voltage.
Is the voltage measured as expected?