Add-A-Wire Manual
50
Installation Instructions
Wire Connections
If the terminal designations on your old thermostat do not match those 
on the new thermostat, refer to the chart below or the wiring 
diagrams that follow.
  Wire from the    Install on the   
  old thermostat  Function  new thermostat 
  terminal marked    connector marked
  G or F  Fan  G
  Y1, Y or C  Cooling  Y1
  W1, W or H  Heating  W1/0/B
  Rh, R, M, Vr, A  Power  R
 C  Common  C
  O/B  Rev. Valve  W1/O/B*
  W2  2nd Stage Heat  W2
  Y2  2nd Stage Cooling  Y2
  W3  3rd Stage Heat  W3
  OUT -  Outdoor Sensor  SENSOR
  OUT +  Outdoor Sensor  SENSOR 
* O/B is used if your system is a Heat Pump.










