7
Terminal descriptions
G
Fan
Rc
Cool transformer
Rh
Heat transformer
O/B
Heat pump reversing valve
Y
Y1, Y2: Used for 1 - 2 stages of conventional A/C
or 1 - 2 stages of heat pump compressor
W
W1, W2: Used for 1 - 2 stages of conventional heat
or 1 - 2 stages of auxiliary heat with heat pump
C
24VAC common
ACC
Accessory (+/-): Used for dehumidifiers,
humidifiers, ventilators, HRVs or ERVs
Warning!
ecobee3 is designed for 24VAC with a 2A
maximum current. Do not connect it to line (high)
voltage or millivolt systems.
