Hi all,

Need some advice. I live in the southwest area(El Paso) and have
turned my gas fired furnace on. I cool my house with and evaporative
cooler located on the roof. When I shut down the cooler and fire up
the heater I have to open/close a flapper vent located above the
furnace. My question is: Is this vent suppose to be open or closed
during furnace operations?

TIA