The Caleffi 521519AC 3-Way Thermostatic Mixing Valve is an essential part that mixes cold and hot water to get the required temperature at the outlet for different usages in HVAC systems. This valve has a 3/4” sweat connection and is designed to use a thermostatic element that controls the flow of cold and hot water so that a user cannot be scalded or receive a thermal shock. #Cale... https://www.partshnc.com/521519ac-caleffi-3wtherm-mix-valve-34-swt