The ecobee has the ability to recognize whether your system is a geothermal heat pump or an air-to-air heat pump. In order for the ecobee to make this distinction, you will need to be sure to configure your equipment properly upon set up.
If you're unsure whether or not your equipment is configured correctly, you can check and adjust by going to:
MAIN MENU > SETTINGS > INSTALLATION SETTINGS > EQUIPMENT > HEAT PUMP > TYPE