Ranch, unfinished basement. Natural draft furnace, and natural draft WH next to it. This return looks to be approximately 10’ away from furnace (I didn’t actually measure it.)
I felt suction at this return. The other return is in the hallway on the floor above. So this is not the “sole” return. Is this still a back drafting concern? Is an unfinished basement still considered to be in the same space? And if its no concern in this case, would it be a concern if the return would be closer to the furnace? If I’m off base here please direct me to the proper place to do more research.
I cannot tell from the picture the distance from the return grille, but it does look like it’s 10+ft. If I could not tell by eye that the distance was easy 10+ft, I would measure it. Anything less than 10ft+ would get reported. Furthermore, you must have at least equally sized supply ducts in this basement. Otherwise, no problem.
Is that chimney going through a return air?