Low Voltage Terminal Description Notes
R 24V power Power to the low voltage
thermostat.
W1 Heating Stage 1
Thermostat connects R to
W1 for first stage heating.
Note: A jumper between W1
and W2 will initiate W2
speed.
W2 Heating Stage 2 Thermostat connects R to
W2 for second stage
heating.
Y1 Cooling Stage 1 Thermostat connects R to
Y1 for first stage cooling.
Y2 Cooling Stage 2 Thermostat connects R to
Y2 for second stage
cooling.
G Fan Thermostat connects R to G
to energize fan for
ventilation speed.
C 24V common Common return from the
thermostat ā not required
for all thermostats.
Boiler
T Boiler / Aux
Call for heat dry contact
T Boiler / Aux Call for heat dry contact
2-Stage Heat ("Auxilary" / O/B)
Com Common for O/B,
Compressor, Humid, De-
humid
S1 O/B Reversing valve
Connects to reversing valve
on heat pump. Energized
with 24VAC during cooling
by default: can be set by
app to energize during
heating.
S2 Not used
2-Stage Cool (Compressor)
Com Common for O/B,
Compressor, Humid, De-