Heating Method Hot Water AHRI Net BtuH 248 000 BtuH Heating Capacity Input 350 000 BtuH Heating Capacity Output 286 000 BtuH Annual Fuel Utilization Efficiency 82 Percent Boiler Type Commercial Gas Fired Water Heater Vent Diameter 5 in Return Connection Size 1 1/2 in Free Air CFM @ 10 Vacuum 1 1/2 in Series Spectrum Overall Height 32 in Overall Width 33 in Overall Depth 25 1/4 in Compatible with Product Type HVAC and Refrigeration Manufacturers Warranty Length 5 yr