Furnace Ducting - Terrible Workmanship

[scottz]

I was trying to figure out why I did not have any air flow to the bedroom furnace floor register and found this behind the front compartments rear wall. They box in two of the frame rails to create an air duct that feeds the bedroom register. The entrance to this air duct is behind the wall, above the vacuum. Apparently the duct was in place first and whomever installed the vacuum simply disregarded the fact that a furnace duct was there and shoved the vacuum in breaking the duct off. Bad design, there is no way the duct and vacuum can occupy the same place.

Not sure what my options are. About the only thing I can think of is to relocate the vacuum. Of course, that will leave a big hole in the wall. Let me know any suggestions.

The other thing I cannot figure out is how heated air gets to the kitchen/living room registers. Looking through the registers it is also a duct made by boxing in frame rails. However, there are only three outputs off the furnace (last photo); the large one is the one that is supposed to go to the bedroom (broken off), one of the small ones goes directly to a vent in the floor of the bathroom, the other small one hangs down in the under belly, not connected to anything. So, how is air getting to the kitchen/living room registers (3)? I verified that heated air is coming out of them. Do you suppose they are using the entire underbelly as a plenum? Or is that small duct supposed to connect to something? I'll have to pull the under belly cover off to figure it out; not happy about that.