Gas and Oil Home Heating Furnaces - Soot stains at vents

I have the Honnywell gas furnace in the atic, last year i noticed soot stains in all the rooms at the sides of the forced air vents. Cleaned them all, now this year i started with a new air filter, and its doing the same thing, i had the gas company come out they inspected the furnace and said everything looks fine. Inside the house tested for carbon monoxide all ok. The guy did not know what was causing this. My thought is like a carbed engine too rich a mixture, but i looked at the flame in the furnace and it is blue color. The smart valve was replaced four years ago, because the unit was shutting off.
Any help thanks

Hi uksparky
It's probably not "soot" stains, just dust. I know, you have a new filter, but that doesn't get it all. To avoid the "lines" where the vents don't sit flush with the walls/ceiling. Go to your hardware/big box store, and find the thinnest, lowest density (ie: "squishyist") self adhesive weatherstrip foam you can. Put it all around under the vent lip where it contacts the wall/ceiling. This should solve your problem.

As to the filter, how often do you change it? What kind is it? I change mine monthly during the heating cooling seasons. Don't believe the 90 day claims from the high efficiency filters...45-60 is probably max, depending on how often your unit runs.

Best in 2008

Hi uksparky
It's probably not "soot" stains, just dust. I know, you have a new filter, but that doesn't get it all. To avoid the "lines" where the vents don't sit flush with the walls/ceiling. Go to your hardware/big box store, and find the thinnest, lowest density (ie: "squishyist") self adhesive weatherstrip foam you can. Put it all around under the vent lip where it contacts the wall/ceiling. This should solve your problem.

As to the filter, how often do you change it? What kind is it? I change mine monthly during the heating cooling seasons. Don't believe the 90 day claims from the high efficiency filters...45-60 is probably max, depending on how often your unit runs.

Best in 2008

Thanks Vic
My filter is from wall mart the type that can adjust in size and wash clean, it has two layers one black other blue, i clean every month, the black part has all the dust, the blue looks clean. Plus i use duct tape on the edges to seal it in the intake.

Do you burn a lot of candles in the house? These will cause what you describe and a lot of time even worse conditions on your drywall and such.

Do you burn a lot of candles in the house? These will cause what you describe and a lot of time even worse conditions on your drywall and such.



I agree that candles are a frequent cause of such problems. Also, just the volume of air being blown against walls can cause this.


The prime thing to verify would be sooting/carbon monoxide from the furnace itself, which was ruled out by the gas co repairman.

So I'd be looking at sontamination of your room air or just the volume of air flow causing the problem.

does your wife or yourself burn candles
they will cause what you have discribed

sorry just started and didnt roll down and see the other same posts

"Ghosting"?

http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/98/980109.html
http://www.buildingscienceconsulting.com/resources/misc/black_stains_on_carpet.htm
http://www.a-aexteriors.com/commercialtesting.html

MT
Great links, more info than I can absorb at one sitting. Already save 'em to my "good info" folder.

Best in 2008