Heating Method Steam AHRI Net BtuH 64 000 BtuH Heating Capacity Input 103 000 BtuH Heating Capacity Output 85 000 BtuH Annual Fuel Utilization Efficiency 82 Percent Boiler Type Atmospheric Vent Steam Boiler Vent Diameter 5 in Return Connection Size 2 in Free Air CFM @ 10 Vacuum 2 in Series Bermuda Overall Height 40 7/16 in Overall Width 16 in Overall Depth 28 in Compatible with Product Type Home Heating Systems Manufacturers Warranty Length 1 yr Limited Includes LWCO Damper