Lochinvar® KNIGHT® Fire Tube Boiler Boiler With ECM Pump, Model: WHB399, 120 V, 4 A, 60 Hz Frequency, 1 ph, 95 % AFUE, 399000 Btu/hr BTU, 6.5 gal Capacity, 38 gpm Flow Rate, 80 psi Pressure, MNPT Connection, Natural Gas Fuel, Direct Vent, Modulating Burner, Chimney/Breeching/Vent Size: 4 in, 377000 Btu/hr DOE Heating, Ignition System: Direct Spark, Direct Spark Ignition, Net BTU Rating: 328 mbh, Number of Boilers: 8, 36.58 sq-ft Area, Wall Mounting, Stainless Steel, Dimensions: 43-5/8 in H x 25-1/4 in W x 21-7/8 in D, Additional Information: 3/4 in Gas Connection, 1-1/2 in Water Connection