Watts 0066606ETX-30 Pressurized Expansion Tank

The Watts 0066606ETX-30 is a 4.5-gallon diaphragm-type pressurized expansion tank that absorbs the extra water volume generated during heating in closed-loop hydronic systems and helps maintain system pressure below the relief valve setting. It uses a carbon steel, epoxy-coated tank with a butyl rubber diaphragm and a 1/2 in. MNPT connection; it includes a 12 PSI air precharge and has an acceptance volume of 2.5 gallons at 12 PSI, a maximum working pressure of 75 PSI, and a maximum operating temperature of 220°F. Designed for both residential and commercial heating, it supports vertical or horizontal mounting in closed-loop hydronic and radiant heating setups and uses non-potable water as service media. Common replacements include Watts ETSX-30, Amtrol Extrol No. 30, and Bell & Gossett HFT-30 expansion tanks.