User's Manual

8 9
Installation
I1 & I2—Indoor Air Quality control output
C—Common (optional when powered by batteries)
O/B—Reversing valve
Y—First-stage cooling / compressor
Y2—Second-stage cooling / compressor
G—Fan
RC—24VAC supply cooling
1
R—24VAC supply heating
1
W2—Second-stage heat / auxiliary
W—First-stage heat / auxiliary
L—System fault indicator (optional) (heat pump only)
S1 & S2—Outdoor temperature sensor (included)
T1 & T2—Remote temperature sensor (optional)
1
Jumper between RC & R is used in single-transformer systems (see wiring diagrams).
Outdoor temperature sensor (included)
Outdoor temperature can be measured by attaching the included sensor to the
S1 and S2 terminals. The outdoor sensor must be enabled in the thermostat’s
Installer Setup menu.
Heat pump models can use the outdoor temperature to eectively utilize the
heat pump:
• When the outdoor temperature is less than the Low Balance Point, the heat
pump is locked out and only auxiliary heating is used.
• When the outdoor temperature is higher than the High Balance Point, the
auxiliary heating is locked out and only the heat pump is used to provide
heating.
Indoor Air Quality functions can use the outdoor temperature sensor to:
• Control humidification setpoint based on outdoor temperature to prevent
condensation.
• Lock out humidification for temperatures over 60°F (15.6°C) or below -30°F
(-34.4°C).
• Lock out ventilation based on high and/or low outdoor temperatures.