Used 423 Sq Ft. U-Tube Heat Exchanger. Mfg by Energy Exchanger 1987. Carbon steel Shell (SA-516) rated 150 PSI @ 500 deg F; Carbon Steel Tubes (SA-214) rated 150 PSI @ 500 deg F. Carbon Steel Heads (SA-515). Shell - 21.25" dia. x 17'2" L ; (70) Tubes - 3/4" dia. Flanged Nozzles: (1) 14", (2) 10", (2) 3", (2) 3/4", (1) 1.5". Type AJU. S/N: X-2915, NB# 1271.