The 649A-XP-6 is a part of Marathon’s XP Series Water Heaters, which are designed for commercial and industrial applications. The 649A-XP-6 is a gas-fired Power Burner model water heater. It has a maximum Input of 6,487,000 BTUs/hr and a maximum Output of 600,000 BTUs/hr. The gallon capacity of the 649A-XP-6 is 500 gallons and is constructed from 304L stainless steel. It has a thermal efficiency rating of 83%. The 649A-XP-6 features a premix power burner, Honeywell power control, sealed combustion and Venturi air delivery systems, low NOx emissions, and is ASME-rated for pressure/temperature safety standards. This water heater can be used for building and process hot water applications, heating swimming pools, and other industrial and commercial uses.