Installation Ecobee3 Smart Thermostat Confusion
The Ecobee3 automatically handles the Rh vs Rc thing, so just connect your R wire to either Rh or Rc.
You can connect Y to Y only on the Ecobee3 and configure it for heat pump operation
W2 connects to W1 on the Ecobee -- this is your axuiliary heat
Yes, O on your old 'stat does connect to O/B on the Ecobee.


See this diagram for more info.