DOE 2021 compliant - If boiler is fired at .75 gallons per hour: 105,000 BTU input - 92,000 BTU heating capacity - 86.5% AFUE - If boiler is fired at 1.00 gallon per hour: 140,000 BTU input - 121,000 BTU heating capacity - 85.5% AFUE - 17.40 gallons water content - Cast iron sections with steel push nipples - Insulated deluxe powder coated steel jacket - Wet base section design - Full plate swing out burner door - Probe type low water cut off - Skim tapping - Pressure control - Tankless opening with cover plate