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neilkent 10-07-2011 02:02 PM

Cold air coming out from vent once furnace stops
I really need your help to figure out what's going wrong.

Bought a house (built in 2006) with furnace located on attic. At night, when it's getting cold, the furnace starts to work, and it's fine. But when it stops, I can feel some cold air coming out from vents.

Even worse, the downstairs has no such problem. it only happens in two upstairs bed rooms!:(

My wife did a quick search and suggested it's back draft damper problem. But why other rooms are OK if it's damper problem.

I check the duct tape and it seems OK.

Thanks for your any advice.



gregzoll 10-07-2011 04:37 PM

The main question is, are the ducts insulated. If you are getting cold air after the unit stops running, there is air leaking into the duct work some way, which needs to be checked out.

Marty S. 10-07-2011 05:25 PM

I'd like to know a real temperature of the air please. Also measure the temp at the other vents upstairs so we have something for a comparison.

Doc Holliday 10-07-2011 07:02 PM

So the heat cycle satisfies and the heat stops but in two rooms only you can continually feel air as if the blower is still spinning? Is that right? That strong?

For how long? And as Marty has already asked, we'd need some air temperatures, please.

biggles 10-07-2011 08:18 PM

was it always like this upstairs?is the return ducted to the back of the attic unit?is the attic cold when the unit is running?also a biggie here check 360 degrees around the 2 conections of the furnace make sure the bottom is sealed tight on that return and the furnace induced draft or static vented?......just asking:whistling2:

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