Used 2685 Sq Ft. U-Tube Heat Exchanger. Mfg by Energy Exchanger 1988. Carbon steel Shell (SA-516) rated 300 PSI/FV @ 650 deg F; Carbon Steel Tubes (SA-214) rated 150 PSI @ 500 deg F. Carbon Steel Heads (SA-516). Shell - 3'8" dia. x 21'5"L ; (322) Tubes - 1" dia. Flanged Nozzles: (5) 18", (1) 14". S/N: X-2965, NB# 1299.