NTI Boilers Firetube Boiler 95.6% AFUE 9.4:1 Turndown, 2200k-Input, 2,103k-Gross Output, 1710 lbs, Water Content-51 gallons, 3" Groove Joint Heating Connections, 1-1/2" MPT Gas Connection, 8" Vent Size, Dimensions-60-5/16"D x33-7/8"W x66-1/4"H