[TAKPAK]

Hi Tom. First, I'm assuming that by "vents" you are referring to what's called the supply vents, the round ones in the ceiling?

There is a whole list of things that could be causing your problem. First, most people with the new "quiet" system (i.e. the two return vents, one on each side of the living room) have found that the return duct is sometimes collapsed partially up in the ceiling. I found mine to be this way. I inserted a couple of PVC pipes into that area to hold it apart. I used open pipes so the air would not be blocked. Also, you would not believe the amount of sawdust that I vacuumed out of the ductwork, both in the ceiling and the floor ducts. The other thing is the bedroom unit may or may not be ducted to the rest of the system. Also, on our older 3400, one of the ducts up in the ceiling had separated, blowing air right into the "attic" area.

Regarding the furnace duct, you should have ONE loose hose from the furnace laying down in the belly area, to keep things from freezing up. Again, there is the possibility that a duct has come loose, or something is blocking it. Remove one of the floor vents, lay a flashlight in it, then use a mirror and look both ways down the duct. Might be surprised at what you find.

Hope this helps.