The Arcotherm JUMBO Series is a duo of portable indirect-fired heaters offering nominal heating outputs of 600,000 and 800,000 BTU’s. Both versions can be outfitted with either a gas (natural gas/propane) or an oil (diesel/kerosene/jet fuel) burner. Indirect-fired heaters produce heat by creating a flame in an enclosed combustion chamber. The exhaust created in the combustion process then makes its way through a four-pass heat exchanger and finally expelled through a chimney located at the top of the heater. A custom exhaust vent can be attached to fit any application in order to safely expel the exhaust fumes when used in indoor applications. A powerful axial fan located at the back of the heater forces ambient room or atmospheric air through the unit, over and around the hot combustion chamber, and expels the freshly heated air out of the front of the unit. This expelled hot air can either blow freely or be ducted in one, two, or four directions to specific areas. The axial fan provides a balanced compromise between efficiency (90%), low noise, and static pressure (a feature particularly useful when ducting is required). The JUMBO Series heaters come with a rugged bearing structure containing various lifting points, handles and supports making them ideal for use in tougher applications, such as agriculture, heavy construction, mining, oil & gas, rentals and large outdoor structures.