IO Hvac Controls ZP3 HPS ESP KIT Control Kit 322838 753 Precise Pressure Sensing: Utilizes time tested Precise Pressure Sensing: Utilizes time tested bellows technology to maintain a 9 PSI fixed differential for consistent performance across non corrosive refrigerants Smith 100208100 2" Flange Gasket is a high performance OEM replacement part engineered for demanding boiler and water heater applications Auto changeover functionality provides seamless transition between heating and cooling modes for multi zone demand this kit simplifies HVAC zoning system design by removing the need for complex bypass ducting in tight mechanical spaces