NTI Boilers Watertube Boiler 94% AFUE 5:1 Turndown, 500k-Input, 470k-Gross Output, 320 lbs, Water Content-3.3 gallons, 2" FPT Heating Connections, 3/4" MPT Gas Connection, 4" Vent Size, Dimensions-32-1/2"D x17"W x43-1/4"H