Source 1 S1-TBSU304-S Owner's Manual & Installation Instructions page 16

Installation Instructions
The Thermostat Backplate
R
G
W1/O/B
W2
Y1
Y2
W3
HUM
DEHUM
R 24 VAC return
G Fan relay
W1/O/B 1st stage heat circuit
W2 2nd stage heat circuit
Y1 1st stage compressor relay
Y2
2nd stage compressor relay
HUM
Humidifier control circuit
DEHUM
Dehumidifier control circuit
IMPORTANT: This thermostat requires both R (24 VAC Return) and
C (24 VAC Common) be connected to the backplate terminals.
C
AUX
C
OUTDOOR
SENSOR
REMOTE
SENSOR
DRY
CONTACT
11
To remove the thermostat
backplate: Gently separate
the display from the base by
pulling first from one side,
then the other until the two
pieces unsnap.
When stat is NOT mounted on wall...
24 VAC common
Outdoor sensor
connections
Remote sensor
connections
Dry Contact
connections