H300FDN BTUs: 300000 BTUs, Fuel Type: Natural Gas Features: -Low nox heater.-Available in several BTUs.-Available in Natural Gas or Propane fuel type.-Performance to save energy and protect against the damaging effects of erosion from high flow conditions for improved reliability.-Forced draft system constantly moves air through the combustion chamber at a precise flow rate.-Eliminating all outside weather variables that can affect the heating performance.-Patented single header "V" baffle design heat exchangers.-Constructed with highly resilient Cupro Nickel for greater durability and longevity.-Easy-to-read L.E.D.-Control Panel provides digital temperature readout.-Diameter plumbing systems with 2" x 2.5" CPVC unions. Warranty: -1 year warranty.