PAX84-150 - Potable Water Expansion Tank - 22 GallonTaco PAX84 150 Potable Water Expansion Tank 22 Gallon The Taco PAX Series expansion tanks are engineered for commercial and residential potable water systems. Designed per ASME Section VIII, Div. 1, these vertical bladder style tanks feature a field replaceable heavy duty butyl bladder that separates air from water to manage thermal expansion effectively. The precharged air chamber reduces tank size requirements by up to 80% compared to standard steel