The Stream33 30 Hydronic Expansion Tank is a diaphragm type hydropneumatics tank designed for pressure control of residential and commercial hydronic heating systems. A pre-charged air chamber allows for system water expansion. The air charge is controlled by a charging valve located on the top or bottom of the tank. This tank is well-suited for various high-demand heating applications with a maximum temperature rating of 240℉ and a pressure capacity of up to 100 PSI. The tank comes with an adjustable factory preset pressure of 12 PSI, allowing for flexibility in different system requirements. The 1/2" MNPT system connection ensures easy installation with most closed hydronic heating setups.