The Lennox 17A30 iHarmony Zone Thermostat is a programmable HVAC control device designed for use with compatible Lennox zoning systems, furnaces, air handlers, and heat pumps. It works by monitoring room temperatures and communicating with the zoning control system to regulate airflow and maintain customized comfort levels in different areas of a building. This thermostat helps improv... https://www.partshnc.com/17a30-lennox-iharmony-zone-thermostat