The following wiring diagrams are for the ecobee3 thermostat and common HVAC equipment configurations.
These diagrams are also available within the ecobee3 Installation Guide included with your ecobee3 thermostat. To download the complete ecobee3 Installation Guide CLICK HERE
For additional guidance on installing your ecobee3 CLICK HERE
CONVENTIONAL HEATING & COOLING
HEAT PUMP (AIR OR GEOTHERMAL) WITH AUXILIARY HEAT
This diagram illustrates the wiring connections for a heat-pump system with auxiliary heating. W2, AUX and or E (Emergency) wiring connections will normally connect to the ecobee3 W1 terminal. ecobee3 manages auxiliary heating through the W1 & W2 (if there is more than 1-stage of aux heat) terminals outputs.
BOILER OR RADIANT SYSTEM WITH FORCED AIR
* If you have 2-wire heat only boiler or furnace system, you'll find additional installation instructions via the following articles:
2-WIRE ACCESSORY (HUMIDIFIER/DEHUMIDIFIER/VENTILATOR)
1-WIRE ACCESSORY (HUMIDIFIER/DEHUMIDIFIER/VENTILATOR)