Reznor's SC separated combustion, gas-fired duct furnaces are designed to separate their combustion air from the air in the heated space. The separated combustion furnace is designed for use in building areas with negative pressure and/or extremely dirty or mildly corrosive atmospheres.

As the leading pioneer in separated combustion technology; these units are designed and manufactured in accordance with the ANSI definition of "separate combustion." Using outside combustion air prevents dirt, lint, dust or other contaminants in the heated space from entering the combustion zone of the furnace.