Aqua-Therm 275, Residential Outdoor Boiler - 80,000 btu • Height: 73" • Length: 72" • Width: 48" • Fire Box Length: 42" • Fire Box Diameter: 32.5 • Firebox Volume: 17 Cu Ft • Door Opening: 19.25"x25" • Water Volume: 59 Gallons • Chimney Size: 6" Double Wall • Weight: 1,450 lbs • Output: 80,000 btu • Electrical Rating: 115v, 1.79A, 60Hz The heating capacity specifications are provided as guidelines only and in no way guarantee the output or capacity of the units. The actual BTU output depends on the type of fuel being burned and its condition, the thermostat setting, the draft adjustments and the chimney into which the unit is installed.