Smoke from first floor fireplace in basement


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Old 02-06-16, 08:37 PM
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Smoke from first floor fireplace in basement

I have a 3 flue chimney, one used for the heat vent, one for the fireplace, the other appeared to be cosmetic. The chimney sweep sealed it off to keep the rain out. Could this flue have been a fresh air vent or some such thing? Can't manage to get the sweep back out to look at the problem. Any ideas?
 
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Old 02-07-16, 12:55 AM
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What are you calling the chimney sweep? Why do you think that one of the flues is cosmetic?
 
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Old 02-07-16, 03:19 AM
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A cosmetic flue is usually just a piece of flue liner sticking up thru the top of the chimney - it wouldn't go all the way down. Generally they are 2' or less in length. If it is a complete flue that terminates somewhere below the attic, then it was put there for a reason [past or future use]

I doubt that the extra flue is for ventilation. I suspect the smoke from the fire is being drawn back down into the furnace flue.
 
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Old 02-07-16, 04:26 AM
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Hi Becki and welcome to the forum,
We will need some more details.
1. Is this your first time using the wood fire?
2. Is it an open fireplace or wood stove?
3. Is the furnace running where that flue might be warm or has it been off long enough to get cold?
4. Is the chimney on the outside of the house exposed to the cold or up through the middle where warmer?
5. Is there a cleanout in the basement for the chimney, could be three of them, and are they closed?

Bud
 
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Old 02-07-16, 06:06 AM
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We have used the fireplace many times. It is an open fireplace. The furnace will come on while the fire is burning and doesn't seem to make much difference either way. The chimney is on an outside wall. There are 3 clean outs and they are closed. The problem didn't happen until the chimney cap was put on (the center flue) and the extra one was sealed off.
 
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Old 02-07-16, 06:13 AM
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3 clean outs means 3 flues so the capped off one wasn't purely decorative. Can you determine where the opening is for the unused capped off flue?
 
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Old 02-07-16, 08:25 AM
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Is the chimney cap on the center flue for the fireplace? And why was the cap installed?

Does the smoke in the basement smell like wood smoke and I assume it only happens when the fireplace is in use. Dumb question, but I want to be sure we aren't dealing with a backdraft issue on the furnace.

Have you gone down to perhaps see where the smoke is coming from, one of the clean-outs or elsewhere?

Do you have a gas or oil water heater?
How old is the house?
How long have you lived there?

Bud
 
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Old 02-07-16, 09:33 AM
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There are only 2 clean outs. The chimney cap is in the center and was put on to keep rain, animals out. Smoke only occurs when burning a fire. Definitely a wood burn smell. Electric water heater, oil furnace. House was built in 1955, been here about a year. The chimney sweep sealed off the other flue. He said it had never been used. Apparently he could tell looking down it.
Downstairs under the fireplace it looks like there is a small amount of ash near the clean out.
 
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Old 02-07-16, 09:59 AM
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The 2 clean outs are on each side.
 
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Old 02-07-16, 11:11 AM
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I'm a bit confused as to 2 or 3 cleanouts, but here is what I'm thinking.
1. The smoke from the fireplace should be 100% contained within its flue, sealed from the air space that surrounds all three flues. If so, then the smoke is exiting the top and being pulled down the other active flue.
2. Or, smoke is seeping out from the fireplace flue into that surrounding cavity and by some path finding its way into the basement, those cleanout doors are suspect or through the barometric damper on the furnace flue. Locate the barometric damper and when the furnace is not running that damper plate should swing slightly open due to natural air flow.
3. The unused chimney may have been used, or cut into to be used, and the opening was later covered with drywall but the hole in the flue was not sealed. Smoke that has entered the cavity around all three flues may have been vented out through this flue and now cannot.

Wild speculation here, but it all revolves around the changes made. Next step, IMO, would be to remove the cap sealing the unused chimney. If that solves the problem, then you will need to determine why, what is leaking where.

You could also seal some plastic over the cleanouts in the basement, but be sure we are talking about the same items. Their door is never a perfect seal and covering with plastic is not a concern. This is a picture of a typical cleanout door: https://www.northlineexpress.com/cle...FRNbhgodKQgGfA

I'll continue thinking and others here are following as well so may add their thoughts.

Bud
 
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Old 02-07-16, 11:38 AM
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We need confirmation on the number of clean outs as that would hopefully verify if the unused flue is real or just decoration.

I suspect the smoke from the fire is being drawn back down into the furnace flue.
I wasn't very clear on that what I meant was the fire smoke might be drawn back down into the other [furnace] flue and then exiting somewhere thru the heat system.
 
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Old 02-07-16, 01:56 PM
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After further investigation, it appears as tho the smoke it coming back in the furnace flue as the fireplace is lower that the furnace flue as you suspected. If I open the door in the basement, the smoke no longer comes in thru the damper plate on the furnace. Now just need to get the fireplace flue higher than the furnace flue. Is there some kind of extension I can put between the fireplace cap and the flue?
 
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Old 02-07-16, 02:21 PM
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My chimney only has a single flue but I had issues with back drafts on windy days and a cap like this one fixed it - Shop Shelter 9-in W x 9-in L Black Galvanized Steel Square Chimney Cap at Lowes.com
 
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Old 02-07-16, 02:21 PM
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Ok, now let's clarify your title.
"Smoke from first floor fireplace in basement " Where is the furnace and where is the fireplace.

I assumed the smoke was in the basement with the furnace and the fireplace was a floor above. Just making sure.

What it might be is the fireplace is drawing so much air that it is altering the pressure balance in the house. A FP is known to be a poor source of heat as it sends more heat up the chimney than it provides for the house, but I love them anyway. But all of that air going up must be replaced by outside air coming back in.

If you crack open a window near the fireplace it might give you the same results as opening the basement door. That's not a fix, but another indication and it may get you by until you decide on what to do with the chimney height.

A more expensive solution, but a win/win would be a sealed combustion wood insert with a nice glass door. I use an older wood stove with a glass door and it is beautiful to sit in front of, provides a lot of heat, and draws in minimal air. Modern ones use outside air for combustion and are even more efficient.

I hope this has helped,
Bud
 
 

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