Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
CH Demand
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure Mains Voltage across terminals, marked 4 (external control in)
and N (Neutral) at the main terminal block.
Note:
If external controls are not fitted a link must be fitted
between 3 and 4 on the main terminal block.
and N (Neutral) at the main terminal block.
Note:
If external controls are not fitted a link must be fitted
between 3 and 4 on the main terminal block.
Isolate as per TOPs P4
and refit as necessary