Furnace getting air from basement instead of return....

We have a furnace that's about 2 years old now. It's in the basement which is a damp, musty place (old stone foundation that's leaking badly courtesy of the torrential downpours we've gotten this season).
As with many homes using forced air heating, ours has an air return. It is directly connected to the furnace -- the air return is a 3 foot square monster, in the floor, immediately above the furnace. For some reason though, this thing is insistent on pulling in air from the basement. To say the least, this is not fun -- it brings that musty odor and mold spores into the living area.
We're working on a solution for the basement water problems ($$$$) but I'd REALLY like to find a way to keep this thing from pulling air from down there in the interim. Suggestions?
James
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Put a dehemidifier in the basement it will stop the mold smell in a few days, then look into your water problem
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Bear in mind, I'm not an HVAC guy -- what should I use to seal it? Typical silicon sealant ok for a job like this? (The sealant of the gods. :) )
James
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There is a mastic sold its like a heavy glue you brush on the joints. I found a brand RCD.You may have to shop around, I finaly went to a plumbing supply store to get it. But if your basement is moldy , kill the mold first with bleach and a garden sprayer , mold will apear dark and will lighten after being sprayed . and get a dehumidifier. Mold present in your basement will permeate your house even with sealed ducts and is caused by excess humidity
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I bought a tub of mastic and a roll of "foil mastic" tape at home depot a while back. The tub of mastic was about $10 and the roll of tape was about $8.
Both the foil mastic and the paint-on mastic have done their job perfectly through several years. The tape is still very firmly attached (I had to remove a piece a few weeks ago and had an awful time getting it off!
A key element is to thoroughly clean the surfaces that you are applying the tape or the mastic to. If the surface is dusty, nothing will hold.
snipped-for-privacy@webtv.net (mark Ransley) wrote in message

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It really depends on the construction. In general the silver tape (not Duct Tape!) works well and is easy to use. A calk or clay like substance is also available for the job and in typical duct work is better.
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Joseph E. Meehan

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is
I'll be having a good friend who does a lot of HVAC come by and look at it as well -- he's been dealing with ducts for about 15 years now, so that will cement the solution well. :) I'll pick up some foil tape beforehand to get a jump on it -- sounds like that's going to be the way to go.
Hopefully we can get a sump pump in there within a few weeks time -- that will do wonders for the water issues. Once that's in, I can get the walls scrubbed down and set up a dehumidifier and air purifier to really clean it out. Sealing the ductwork up better will at least help in the interim (need to insulate the ducts feeding the house as well).
James
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I would wait until he shows up and takes a look, let him pick his tools. Some people do not like any type of tape. BTW I have been told there are some real differences in the good tape some brands/lines being much better than others, but they all are better than the standard duct tape.
It beats me why anyone would want to tape a duck.
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Joseph E. Meehan

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It's a duct. It needs tape. I'll leave you to figure out what kind to use.
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Hi Brad, hope you are having a nice day
On 21-Aug-03 At About 07:38:57, Brad wrote to All Subject: Re: Furnace getting air from basement instead of return....
B> said... >> > Most returns are non too tight. You can try sealing the returns >> up a > little better. Bear in mind, I'm not an HVAC guy -- what >> should I use to seal it? Typical silicon sealant ok for a job like >> this? (The sealant of the gods. :) )
B> It's a duct. It needs tape. I'll leave you to figure out what kind B> to use.
Actually you should never use duct tape on a duct. it doesn't last very long. you should always use the foil tape.
-=> HvacTech2 <=-
.. I think you should get that checked out... - TEC
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