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Two related questions:

  1. I have a problem section of heating vent that is 2.5" x 12". I thought I'd be able to find this size in Lowes or Home Depot, but nothing is even close (I see 3.5" x 10"). Note: This section handles the air into the furnace (from an upstairs register).

The question is: Where can I get 2.5" x 12" or does there exist some place I can order a converter?

  1. The reason for question #1 is a tricky one. I would have to provide some screenshots and way too much info, but I have reason to believe that removing this section altogether might be my best option for now. If I do this, I am concerned that I might be putting too much strain on the furnace.

Here is how it is configured. First, there is a very large air intake register (sorry, I don't know the terminology) upstairs that leads right into the furnace (about 4 feet of 3.5" x 12" ducts). The "problem" duct described above is from another intake register in another room. This doesn't go directly into the furnace. Rather, it comes right in the middle of that 4-foot section of the other air intake. I would imagine that this really doesn't provide that much more air to the furnace, but I could be wrong.

So, to summarize: 1. What to do about odd-sized ducts? 2. Can I just block off that additional air intake, or will my furnace explode? Thanks.

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What is the problem with this section of duct, and why do you think you have to replace it? – Tester101 Nov 3 '11 at 18:21
Rather than connect the duct all the way up to the section of duct running to the in-vent upstairs, they simply nailed a huge sheet of aluminum to the joists, then attached the duct coming from the furnace to the aluminum sheet. So there is a "box" created by the ceiling, 2 joists, and a bunch of aluminum. It's way too complicated. I tried to draw it. I'm thinking I need to get some photos of this. Not only is this a mess, I think it may actually be pulling in some air from the crawl space under the attached porch on that side of the house. I am smelling a musty/moldy smell. – user980 Nov 3 '11 at 18:45
I want the air to be pulling from the upstairs - not from the basement (and elsewhere). – user980 Nov 3 '11 at 18:47
Creating a return vent in that way is very common. sealing any connections with metal tape, will prevent it from sucking air from unwanted places. – Tester101 Nov 3 '11 at 19:21
There may be some structural issues that are causing some air (potentially smelly air from under the porch) to be sucked in. I just want to go straight up to the stretch of duct going up to the wall. – user980 Nov 3 '11 at 19:43

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