Used 966 sq ft 316L stainless steel horizontal shell and tube heat exchanger. Manufactured by Ward Tank and Heat Exchangers. 316L stainless steel heads. (328) 3/4" diameter 316L stainless steel tubes, rated 150 psi @-20 to 302F. SA-516-70 Shell, rated 150 psi @-20 to 302F. National board #3637, serial #HC-6168. Built 2006.