5-277-04-072-001

Built around a double-wall two-pass U-bend bundle, this configuration delivers in-tank heating with boiler water in the tubes and cross-contamination protection for demanding service. The vented air gap between tube walls gives a visible telltale leak rather than allowing boiler water and tank contents to mix. Its envelope centers on a 4-inch diameter shell in a 2-pass arrangement. It carries 3/4-inch O.D. tubes. That combination is cataloged as 5-277-04-072-001. Standard construction uses cast iron bonnets, steel shell, and copper (double wall) tubes. The unit is rated for 150 PSI on the shell side, 150 PSI on the tube side, and 375°F maximum temperature. The series sees regular use in potable water storage tanks, institutional and health care water storage, and glycol-fed storage heating.