Used 15 sq ft. ITT standard stainless steel shell and tube heat exchanger. 6" diameter X 24" long. Shell rated 225 PSI @ 20 to 450 degrees F. (116) 1/4" stainless steel tubes rated 150 PSI @ 20 to 450 degrees F. National Board # 50638. Built 1991. 2" service inlets and 3" process inlets.