Used 469 Sq ft Carbon Steel fin fan heat exchanger. Manufactured by Fabsco. (3) tube sections with a total of (112) 1" diameter x 192" long carbon steel tubes rated 150 psi @ 450F. (2) 6' diameter fans 7.5 HP motor. (6) 2" inlets, (6) 2" outlets. Serial # A13-10798-2C. National Board # 7819. Built 2013.