Set Appliance State:

Set Multimeter to AC Volts Set meter to measure AC Volts
Isolate Mains Power to appliance as per TOPs P4
Remove plastic cover from control box
Selector switch to hot water position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure voltage across the live connection marked L3 (brown wire) and the neutral connection marked N2 on the molex plug next to the transformer (CN1/CN4) on the main PCB.