Set Appliance State:
Set Multimeter to AC Volts 
CH Demand
Isolate Mains Power to appliance as per TOPs P4
Open the control box by removing the two securing screws and lower the access door
Draw the control board forward to allow access to the PCB
Ensure the room thermostat (if fitted) is calling
Open the control box by removing the two securing screws and lower the access door
Draw the control board forward to allow access to the PCB
Ensure the room thermostat (if fitted) is calling
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across terminals SwL and N on the main connector block.
Note:
If no external controls are fitted ensure a link is present between SwL and L.
Note:
If no external controls are fitted ensure a link is present between SwL and L.
Isolate as per TOPs P4
and refit as necessary