Furnace/Heating/AC problem

When my furnace is on, there is cold air coming out of two large vents in my house while warm air is coming out of all the other heating vents. Is it possible that the heating and air conditioning are on simultaneously? My thermostat allows only for EITHER heat OR cooling. You can't turn on both at the same time. What is going on? By the way, I had the furnace cleaned about 6 weeks ago.
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my>house while warm air is coming out of all the other heating vents. Is it>possible that the heating and air conditioning are on simultaneously? P.S. I forgot to mention that the house has only one thermostat in the living room, and I have gas heat. The thermostat has a setting for "cool or off or heat" on the left side, and "fan or auto" on the right side. I have it set on heat and auto.
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No ,if heat is out of one duct it is your ducts, probably uninsulated and long
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On 14 Nov 2004 06:45:36 GMT, snipped-for-privacy@aol.com (Chemqueries) wrote:

My guess, since I can't see it from here, would be uninsulated ducts going through a cold area, cooling the warm air before it comes out.
Gary R. Lloyd CMS
http://www.techmethod.com
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Are you sure those "two large vents" aren't the return vents? (Some call them cold air returns)
When the unit is running, take a paper towell and see if those two vents will suck the towell up into them......
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those two vents >will suck the towell up into them....
Hi. I did put a piece of paper near those two vents and, yes, the paper is drawn TOWARDS the vent, which really surprised me. When I put my hand near those vents, it feels as if cold air is coming out, but apparently it is being drawn in. I didn't know there were such vents! Thank you for your help.
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Strange how that works. It DOES feel like it's blowing cold air out and not drawing it in.......
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snipped-for-privacy@aol.com (Chemqueries) wrote:

In order for something to blow out, there must be an intake, or you would create a vacuum, and the house would implode.
The coolness you feel is "wind chill" from the air movement over you hand. I've always heard them referred to as "cold air return" even when they are up high and return hot air for the A/C.
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it could be that the side of the hand toward the vent, may have a lower pressure cusing a more chilled effect to be notived instead of in front of the air flow making it seem to feel as if the wind is more present on the backside ? Of course this works with high speed air flows, not sure how noticable would be at that low of air speed ?
(Chemqueries) wrote:

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high and return hot air for the A/C.
Very interesting. I was just going to post and ask why it feels as if cold air is being blown out. I guess you're a mind reader!
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Thanks to all for your replies. As "Red Neckerson" suggested, I think those two vents are return vents.
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On 17 Nov 2004 07:24:06 GMT, snipped-for-privacy@aol.com (Chemqueries) wrote:

Mystery solved. Big bonus points for Red Neckerson. Good call.
Gary R. Lloyd CMS HVACR Troubleshooting Books/Software http://www.techmethod.com
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(Chemqueries) wrote:

I was at a home yesterday that had 2 return vents and ONE supply in a bedroom! Now, the house has been going through some remodeling (for the past 6 years!) and it may have been 2 different rooms turned into one. Returns in the floor and supplies in the ceiling. Not a very good setup.....
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(Chemqueries) wrote:

A lot of people would disagree with that statement. If the returns and supplies are in the ceiling, don't you think the heat would naturally stay near the ceiling? Having them split between ceiling and floor would force some air to be pulled down.
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(Chemqueries) wrote:

Agreed.
I have seen houses that have high wall vents and low wall vents with dampers to close one or the other off (high ones used in summer and low in winter)....
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Not as bad as you might think, though. With the returns in the floor, you suck
the cold air out, and the warm air moves more or less uniformly down to fill the remaining space. If you do it the other way, you get more turbulence, and the air coming out of the duct can go straight up, without dispersing, and get sucked out the return vent without ever warming the room.
--Goedjn
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