Set Appliance State:

Mains Power Off
Gas Off
Set Multimeter to AC Voltage Set meter to measure AC Volts
CH Demand
Boiler Operating Switch in HW and CH position
Heating Control Thermostat adjusted to Maximum
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the voltage across connection 11 (Orange wire) and connection 13 (Pink wire) on the R/H connector block.