If you're posting a request for installation help, please provide as much info about your system as possible. For example, for help regarding connecting a smart thermostat, please include details about your system including whether you have gas/electric, heat pump, number of heat stages, A/C condenser, etc.
I have an Ecobee 3 connected to a 3 zone Zoneatrol Board to a Carrier furnace.
Once the fan turns on it never turns off. If I reinstall the old HOneywell Thermostadt it works fine.