A fluid directing structure for a direct fired appliance having a heating space, a burner for providing heat to the heating space, and an exhaust includes a duct. The duct includes a first passage extending from a first end adjacent the burner to a second end fluidly connected to the exhaust. A second passage extends from a first end fluidly connected to the first passage to a second end fluidly connected to the heating space. A damper is connected to the duct and has a first condition directing fluid flow from the first end of the first passage to the second end of the first passage while preventing fluid flow to the second passage. The damper has a second condition directing fluid flow from the first end of the first passage to the second passage while preventing fluid flow to the second end of the first passage.
