Used 765 Sq Ft. U-Tube Heat Exchanger. Mfg by Energy Exchanger 1988. 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 - 17.25" dia. x 20'4" L ; (105) Tubes - 3/4" dia. Flanged Nozzles: (2) 6", (2) 4". Type AEU. S/N: X-2967, NB# 1305.