The ZoneFirst ZPS Zone Plenum Sensor is an HVAC monitoring device designed to measure temperature within a zone plenum or duct system. It works by sensing changes in air temperature and providing feedback to the zone control system, helping regulate airflow and maintain balanced comfort throughout a building. The sensor is commonly used with zoning systems, forced-air furnaces, air co... https://www.partshnc.com/zps-zonefirst-zone-plenum-sensor