Ecobee thermostats now have the capability of adding a Remote Sensor Module (RSM) that enables you to connect up to 4 remote sensors to your ecobee smart thermostat. The RSM is pre-configured to support the following sensors.
Honeywell C7189U indoor sensor and C7089U outdoor sensor
Tekmar D076 indoor sensor and D079 slab sensor
Johnson Controls HT-6703 humidity sensor
Other temperature sensors can be supported by just entering the B value or the resistance reported by the sensor at 70°F during the configuration process
What remote sensor would you use if you wanted to monitor the discharge air temperature? None of the above pre-configured sensors have a high enough operating range to handle the high discharge temperatures, say above 130°F. Therefore I would recommend using the Jackson Systems Z-600-DAS. This is the discharge air sensorused on our Z-600 panel. It is a Type 3 NTC 10k ohm sensor and will work with the ecobee thermostat. The Z-600-DAShas a resistance value of 11,903ohms at 70°F. This is the value in need to enter during the configuration process. The Z-600-DAS has an operating range of 0-180°F