One vent for my central AC isn't working? How Can I fix it?

Question

I have central AC in my house and all the vents work fine except for one. No air is coming out of it and I'm not sure if it ever has or not, its behind my couch, so I've never really paid much attention to it until now.

Did whoever install it just forget about that one vent? I've taken the cover off to see if something was in there blocking air flow but couldn't feel anything. Any advice on how to fix this problem?

Answer 1

it is probably a cold air return vent

Answer 2

yes ,air return vent, try blow some smoke to make sure if it suck it or try cover the vent with  tissue paper ...good luck

Answer 3

Assuming that when you removed the register cover, you saw or felt the supply duct, the supply line to that register is probably disconnected at the trunk and is just blowing under your home.  If installed correctly, this really shouldn't happen, but unfortunately.....not everyone takes the pride in their work  they should.  There are generally "tabs" that are bent inside of the trunk line to secure the branch line.  Lots of things can be wrong but most likely is the hole in the trunk line wasn't cut properly and the installer counted on the tape holding (a few days at least).  It's fairly easy to fix but get the good "metal" like duct tape (The back has to be peeled off) and after you get the tabs bent as well as you can, seal it up with the good tape (wipe down the dirty duct first; you'll get a better bond).