A O Smith Burkay Conservationist HW-399 Commercial High Altitude Natural Gas Boiler, 120V, 399000 btu/hr Input, 322790 btu/hr Output, 30 gpm at 20F, 160 psi
A O Smith Burkay Conservationist HW-670 Commercial High Altitude Natural Gas Boiler, 120V, 660000 btu/hr Input, 543000 btu/hr Output, 51 gpm at 20F, 160 psi