Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
CH Demand
Selector switch set to CH/DHW
CH temperature control set to MAX
Preheat switched OFF
Note.
Slightly move connectors until PCB connection strips
are exposed for voltage measurement
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure for AC voltage across pin 2 (X1 connector PCB) and
main neutral (terminal block).
Expected voltage approximately 230 Vac.