Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Gain access to PCB (use Insulation Mat as required)
Central Heating Switch in Constant position
Room Thermostat calling for heat
Central Heating Switch in Constant position
Room Thermostat calling for heat
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Is there mains voltage present on PL1 connection 3 (white) and neutral (blue)?
Ensure link is present if no room thermostat is fitted.
Ensure link is present if no room thermostat is fitted.
Isolate as per TOPs P4
and refit as necessary