Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
CH Demand
Gain access to PCB (use isolation mat as required)
External controls calling for heat
External controls calling for heat
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across live return terminal marked LR and the neutral terminal marked Ns at the green terminal block on the PCB.
Note:
If an external room stat is not fitted or the integral timer is a wireless control then a link should be present between terminals Ls and Lr.
Note:
If an external room stat is not fitted or the integral timer is a wireless control then a link should be present between terminals Ls and Lr.
Isolate as per TOPs P4
and refit as necessary