b. Admit as needed. A manually-operated damper at the front of the air conditioner can be opened to introduce fresh air
into the evaporator airflow. The damper admits outside air upstream of the evaporator filter.
c. Unhook the damper chain from its key slot. Allow the hinge spring to pull open the damper door. Lock door in
described open position by hooking chain in key slot.
When using fresh air for ventilation, a window, door or vent should be opened. If the room or enclosure
is tightly closed, and ovpressure will buildup and decrease the volume of fresh air drawn in.