Smoke smell sometimes in basement

[heavy hammer]

i have a split level ranch house with a masonry chimney two flues. An insert upstairs and a wood stove downstairs. The downstairs is the basement, both flue have been cleaned the insert has a liner the stove is just piped into the masonry. I'm just wondering why sometimes we smell that smokey smell in the basement, and if there is a way to stop it? We will go for a few months with nothing then just one day my wife more than me will ask why she smells that faint smoke smell.

 

[Hogwildz]

Sounds like you have a down draft going on. Especially when burning, if the flues are both same height near each other, the exhaust gases can rise and leave one flue, and drop down the other if it is cold and has a down draft going on.

 

[heavy hammer]

i have thought of this, because the flues are about a foot apart and only about a foot difference in height. The smell has only been noticed when it is warm out like this summer. How would I correct this problem do they make a flue extension, or something I could put on to change the height of one flue without having to add another clay liner?

 

[kennyp2339]

i have thought of this, because the flues are about a foot apart and only about a foot difference in height. The smell has only been noticed when it is warm out like this summer. How would I correct this problem do they make a flue extension, or something I could put on to change the height of one flue without having to add another clay liner?

I don't know where I've seen this but, I saw a diagram showing a double lined flue, one top plate with cap was the normal install, the second had an anchor plate and a piece of class a pipe to a cap with a specific measurement of 18" minimum, meaning that there needs to be 18" minimum separation between the 2 chimney heights, I'm sure its not a code / requirement, perhaps I saw it on an install guide, but it may be something to look into.

 

[yooper08]

The down draft could be caused by a few things and they may even be working together, but smelly down drafts in the summer are more common due to humidity in the air absorbing creosote compounds on its way down.

Since the basement flue sounds like it's just an open flue, you're more likely to get a down draft than if it were lined all the way up just due to the size of the opening.

I would recommend lining the basement stove all the way up and make the flues different heights. Not only could that help, it's safer as well.

Anything outside that would be deflecting wind downward, such as nearby trees or buildings?

 

[Sully1515]

I'm not a true expert at this, but, my previous home was a split level. We would get that smell when it rained, especially during the warmer months. Is there any moisture within the chimney / flue? If so, you may want to consider getting a cap to help stop some of the rain / moisture entering the flue?

During a low pressure, in my previous home, this was common. This is sometimes common in my current home as well.

• Is your chimney / stove pipe within the home or is it along the exterior wall?

• I assume the chimney / stove pipe / flue is higher than the ridgeline of your roof? If not, this could help with you getting a better up-draft.

Again, I'm not certified in any of this, I thought I'd simply comment based on my own experiences with my previous home.

Is it possible to provide pictures? This way, those who have more experience in this subject may be able to help you out with suggestions.

 

[heavy hammer]

The chimney is along an exterior wall, and yes the chimney is well above the ridge line. I have not had any issues with draft either. I do have a chimney cap as well. I do not have any way to block or close the chimney off it is open from the stove up to the cap, by this I mean the flue doesn't have a way to close it off. I have closed the by pass in the kuma downstairs but I assume the smell can still come from the cat. I have thought of putting a piece of insulation or something in front of the cat during non burning months. I have also been told about the different pressure you can get in warmer temps with basement setups.

 

[begreen]

Can you disconnect the stove pipe in summer and plug the thimble?

 

[heavy hammer]

Yes that would be the easiest.

 

[semipro]

A damper on top of the flue that serves the wood stove might also work.