What does economizer active mean?
Economizer Active Indicates that this room’s outside air damper is opened because of an economizer cycle or a demand ventilation cycle.
If the thermostat’s cool set-point is lower than the room temperature and the outside air temperature is cold enough to cool the room on its own, the thermostat will start an economizer cycle.
Demand Ventilation Cycle
If this thermostat has a CO2 sensor and the CO2 concentration levels (ppm) are above the configured CO2 threshold, the thermostat will enable the economizer to increase the amount of ventilation, beyond the minimum ventilation rate, into the room.