NTI Boilers Firetube Boiler 95% AFUE 10:1 Turndown, 285k-Input, 263k-Gross Output, 200 lbs, Water Content-4.9 gallons, 1-1/4" MPT Heating Connections,Inlet: 3" / Outlet: 3" 3/4" MPT Gas Connection, 3" Vent Size, Dimensions-18-5/8"D x21-1/4"W x33-3/8"H