5-277-04-018-001

5-277-04-018-001 is a Diamondback tank heater unit built on a double-wall two-pass U-bend bundle for in-tank heating with boiler water in the tubes and cross-contamination protection. The vented air gap between tube walls gives a visible telltale leak rather than allowing boiler water and tank contents to mix. Physically, the unit runs a 4-inch shell in a 2-pass arrangement. It carries 3/4-inch O.D. tubes. Standard construction uses cast iron bonnets, steel shell, and copper (double wall) tubes. Operating limits are 150 PSI on the shell side, 150 PSI on the tube side, and 375°F maximum temperature. Common applications are institutional and health care water storage, domestic water storage under double-wall codes, and glycol-fed storage heating.