The York 2EC0401 Single Enthalpy Kit is an HVAC control accessory designed to improve economizer operation in compatible packaged air conditioning units. It uses a humidity sensor to measure outdoor air moisture and provide enthalpy information to the control system, helping determine when outside air can be used for cooling. This field-installed kit supports energy-efficient operatio... https://www.partshnc.com/2ec0401-york-single-enthalpy-sensor