Used 877 Sq Ft. U-Tube Heat Exchanger. Mfg by Energy Exchanger 1987. Carbon steel Shell (SA-106-B) rated 150 PSI @ 500 deg F; Carbon Steel Tubes (SA-214) rated 150 PSI @ 500 deg F. Carbon Steel Heads (SA-515). Shell - 19.25" dia. x 22'1" L ; (113) Tubes - 3/4" dia. Flanged Nozzles: (1) 10", (1) 8", (1) 4", (1) 3". Type AEU. S/N: X-2917, NB# 1258.