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
Use Insulation Mat as required
Remove PCB cover
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Reset appliance if it is in lockout.
Test 1:
Measure the voltage at the black wire (pin 5)
at connector X11 to a suitable earth point.
Mains voltage should be present.
Test 2:
Measure the voltage at the brown wire (pin 5)
at connector X13 to a suitable earth point.
Mains voltage should be present.