Source 1 S1-TBSU305-S Owner's Manual & Installation Instructions page 14

Installation Instructions
Wire Connections
If the terminal designations on your old thermostat do not match those
on the new thermostat,
diagrams that follow.
Wire from the
old thermostat
terminal marked
G or F
Y1, Y
W1, W
Rh, R, M, Vr, A
C
O/B
W2
Y2
W3
Ck1
CKGND
* O/B is used if your system is a Heat Pump.
refer to the chart below or the wiring
Function
Fan
Cooling
Heating
Power
Common
Rev. Valve
2nd Stage Heat
2nd Stage Cooling
3rd Stage Heat
Dry Contact Switch
Dry Contact Switch
10
Install on the
new thermostat
connector marked
G
Y1
W1/0/B
R
C
W1/O/B*
W2
Y2
W3
DRY CONTACT
DRY CONTACT