the situation.
I have pictures of almost the entire home on flickr, mostly private pictures, for situations like this. I went wild w/the digital camera.
if what looks like a six inch round pipe between the return air duct and the (furnace/air handler/evaporator coil) is open at the bottom where it is behind the "L" shaped portion of the return air duct.
Not sure what you mean by open. As I recall, it mates up to the duct work there. I'll have to check when I get back to the house.
the roof and has a rain cap, you're in good shape as far as preventing combustion byproducts being drawn into the house.
Yes, this goes to the roof and has a rain cap. I'm assuming this opening allows combustion gases to vent out through it? I really don't know this stuff at all.
finished with this equipment now closed in. Your hiring of a duct man to seal off the return air vent and run a new return into the finished area is the proper course of action and you should have no problems.
He's coming out Sat., and will do the work the Sat. after.
Thanks all! I have a carbon monoxide detector upstairs, which has never gone past 0. I have dogs in the house and would hate for something to happen the times I am gone.