Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
CH Demand
Thermostat to ON position
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure Mains Voltage across the PCB connection X1 on the far right hand side blue wire on connector and the Neutral on the main terminal block.
Isolate as per TOPs P4
and refit as necessary