Smoke from my fireplace entered my basement, creating carbon monoxide ,what can I do?

[Bluelinecop]

Hi all, I'm new to the forum, and I'm glad I found this site. I looked around the net and it seems like you guys have the answers here. Anyway, my wife and I purchased this bi-level home about 6 months ago. Part of the reason for me was the fact that it has a nice marble/wood wood burning fireplace in the living room.

Today was the first day we used real fire wood from the yard rather than those store bought logs. We burned wood for about 2-3 hours, when I went to the garage to let the dog out I noticed that the garage and the basement had a thin layer of smoke. Not enough to set off the fire alarms, but enough to irritate the eyes, and enough to register 35 on the carbon monoxide alarm. This is killing me because like I said half the reason I bought this house is because I always wanted a fireplace. I made sure there was a nice draft when I lit it, and no smoke came into the living room.
Has anyone else experienced this? Thoughts?

 

[djarseneault]

Does the chimney have a cap? If so, what is probably happening is the cap is holding the smoke coming out of the flue you are using long enough for the other flue that is not in use (read cold) to pull some of the smoke in.
I.E. warm flue=rising draft. cold flue=falling draft.

If this is the case, you can try making a divider out of sheet metal to put between the flues under the cap.

 

[snowtime]

Well you obviously have to stop burning until you find the problem. I see 3 possibilities without knowing more. First your chimney is compromised in some way. Get a sweep in to check it. Second you left a window or door open in the basement and the smoke went down and in. It can happen. Third if you have another chimney thats shorter the smoke might of gone down it. If you have more than 1 chimney check the heights of each as they relate to each other. Would help if you supplied info such as chimney height, clearance above roof ETC.

 

[Bluelinecop]

Hmmmm, I don't know the chimney height, but as far as more info goes, the chimney shares itself to the boiler in the basement, however we had central heat placed in the attic, so I don't use the boiler. Can that have any connection?

 

[Bluelinecop]

Does the chimney have a cap? If so, what is probably happening is the cap is holding the smoke coming out of the flue you are using long enough for the other flue that is not in use (read cold) to pull some of the smoke in.
I.E. warm flue=rising draft. cold flue=falling draft.

If this is the case, you can try making a divider out of sheet metal to put between the flues under the cap.

Wait I just read your post again, and YES there are caps on both the chimney AND the boiler flute. But when I looked at the smoke rising out of the chimney it seem to go straight up. Is it common to use the fireplace and not have the boiler on?

 

[begreen]

Hmmmm, I don't know the chimney height, but as far as more info goes, the chimney shares itself to the boiler in the basement, however we had central heat placed in the attic, so I don't use the boiler. Can that have any connection?

Possibly. Do all the flues end at the chimney cap at the same height? If so, smoke can get sucked down the cool chimney. The solution is to extend the flue for the wood burner.

 

[savageactor7]

Blue I agree that it sounds like a plugged chimney cap. If it's not next time the fireplace is dead cold stick your head in there and look up and along the sides. There may be a way to open the vent a little more with a bent poker. Since it sounds like it was mostly closed ...it'll be a dirty job. But if you do find one it and manipulate it a few times will become easy enough to open and close at your discretion. Good luck

 

[djarseneault]

Does the chimney have a cap? If so, what is probably happening is the cap is holding the smoke coming out of the flue you are using long enough for the other flue that is not in use (read cold) to pull some of the smoke in.
I.E. warm flue=rising draft. cold flue=falling draft.

If this is the case, you can try making a divider out of sheet metal to put between the flues under the cap.

Wait I just read your post again, and YES there are caps on both the chimney AND the boiler flute. But when I looked at the smoke rising out of the chimney it seem to go straight up. Is it common to use the fireplace and not have the boiler on?

Not common, I think you found the problem. Now you need a solution. Is it one cap covering both flues, or two sepatate caps? If they are separate just remove one of them and see if that helps. Or you could put a divider between the two (less work than extending the flue).
Divider method works most of the time, but not always.

 

[oldgrezmonke]

Today was the first day we used real fire wood from the yard rather than those store bought logs.

Could that "yard wood" have been green or wet producing more visible smoke than the store logs ? Of course you still need to find why it was drawn inside , you don't want to breathe more than an occasional whiff of wood smoke .

 

[Todd]

I had the same problem, fireplaces cause strong negative pressure in the room they burn in. The house will try to even out this pressure by sucking in make up air from the least resistant source which in your case is the boiler chimney. The smoke is being pulled into your other chimney. You need to extend your wood burner chimney, caps have nothing to do with it keep them on. You will still have the negative pressure unless you can rig outside combustion air to your fireplace or crack a window nearby.

 

[oconnor]

Hmmmm, I don't know the chimney height, but as far as more info goes, the chimney shares itself to the boiler in the basement, however we had central heat placed in the attic, so I don't use the boiler. Can that have any connection?

Possibly. Do all the flues end at the chimney cap at the same height? If so, smoke can get sucked down the cool chimney. The solution is to extend the flue for the wood burner.

Stack effect comes to mind - when you heat the air in the house, it becomes bouyant and looks for a place to act out its rising tendancies - the flue on your fireplace is the easiest way for the hot air to leave, obviously, since it starts in the fireplace. Now that air is leaving the house, it must be replaced, and given that your basement boiler flue is already in a relative negative pressure area when compared to the outside, and is cold given it's lack of use, and you are pumping air out of the house when using the upstairs fireplace, the boiler flue that leads to the basement becomes a supply line for makeup air.

Unfortunately, that makeup air is being taken from the top of the chimney, right next to where the smoke from the fire is leaving, hence the CO alarm levels.

Raising the height of the smoke exhausting flue can improve the quality of the bad air that enters the other flue - but it doesn't decrease the amount of cold air that enters the basement, just decreases how much smoke/CO is in the air that enters the basement.

In the end, all air that leaves must be replaced somehow.

If you are expecting to get a heat benifit from the fireplace, unfortunately your return on effort won't be very high - most fireplaces are about 10% efficent, and some actually create a net cooling effect on the house as they exhaust warm air that needs to be replaced by the cold air outside.

If you want heat, I suggest the solution is an insert stove - way less air is exhausted (10-25 cfm is what I have read), so way less air is brought inside - if you install a stove with an OAK, then next to no home air is exhausted.. If you want fire for esthetics, then cracking a window in the room will work, as well, adding makeup air supply to the fireplace can be done, but is had to do well.

 

[Bluelinecop]

Hmmmm, I don't know the chimney height, but as far as more info goes, the chimney shares itself to the boiler in the basement, however we had central heat placed in the attic, so I don't use the boiler. Can that have any connection?

Possibly. Do all the flues end at the chimney cap at the same height? If so, smoke can get sucked down the cool chimney. The solution is to extend the flue for the wood burner.

Yes all the flues end at the chimney cap and are the same height. It's just hard to belive that the cold flue can suck down smoke from the fire flue all the way to the basement. If I extend the flue for the wood burner wouldn't that cause the smoke from the boiler to then get sucked down the fire flute in the exact opposite effect? I ask because although we're running the central heat, we';re going to use the boiler from time to time just to keep it running well, in case we need it in the future.

Blue I agree that it sounds like a plugged chimney cap. If it's not next time the fireplace is dead cold stick your head in there and look up and along the sides. There may be a way to open the vent a little more with a bent poker. Since it sounds like it was mostly closed ...it'll be a dirty job. But if you do find one it and manipulate it a few times will become easy enough to open and close at your discretion. Good luck

It's clear. As soon as we purchased the house I had a chimney sweep guy come out and check it out. No obstructions or build-up. I think thats what you mean when you mention a plugged chimney cap. (nests etc I guess)

Today was the first day we used real fire wood from the yard rather than those store bought logs.

Could that "yard wood" have been green or wet producing more visible smoke than the store logs ? Of course you still need to find why it was drawn inside , you don't want to breathe more than an occasional whiff of wood smoke .

It was definitely not green, possibly a little wet because we've had some snow. I like the idea of yard wood much more than store logs. the crackling, the smell, it's just different, not to mention free!

I had the same problem, fireplaces cause strong negative pressure in the room they burn in. The house will try to even out this pressure by sucking in make up air from the least resistant source which in your case is the boiler chimney. The smoke is being pulled into your other chimney. You need to extend your wood burner chimney, caps have nothing to do with it keep them on. You will still have the negative pressure unless you can rig outside combustion air to your fireplace or crack a window nearby.

What if I crack a window in the basement then? Would that keep the air from being sucked down from the chimney flue? I forgot to mention this before, and I never realized some many variables came into play just for burning a fireplace, but we have a radon system which sucks out all of the air in the basement and garage floor slabs. Can the lack of air in the basement combined with the cold boiler flue be to blame?

Hmmmm, I don't know the chimney height, but as far as more info goes, the chimney shares itself to the boiler in the basement, however we had central heat placed in the attic, so I don't use the boiler. Can that have any connection?

Possibly. Do all the flues end at the chimney cap at the same height? If so, smoke can get sucked down the cool chimney. The solution is to extend the flue for the wood burner.

Stack effect comes to mind - when you heat the air in the house, it becomes bouyant and looks for a place to act out its rising tendancies - the flue on your fireplace is the easiest way for the hot air to leave, obviously, since it starts in the fireplace. Now that air is leaving the house, it must be replaced, and given that your basement boiler flue is already in a relative negative pressure area when compared to the outside, and is cold given it's lack of use, and you are pumping air out of the house when using the upstairs fireplace, the boiler flue that leads to the basement becomes a supply line for makeup air.

Unfortunately, that makeup air is being taken from the top of the chimney, right next to where the smoke from the fire is leaving, hence the CO alarm levels.

If you are expecting to get a heat benifit from the fireplace, unfortunately your return on effort won't be very high - most fireplaces are about 10% efficent, and some actually create a net cooling effect on the house as they exhaust warm air that needs to be replaced by the cold air outside.

If you want heat, I suggest the solution is an insert stove - way less air is exhausted (10-25 cfm is what I have read), so way less air is brought inside - if you install a stove with an OAK, then next to no home air is exhausted.. If you want fire for esthetics, then cracking a window in the room will work, as well, adding makeup air supply to the fireplace can be done, but is had to do well.

The more I read and respond to all your posts the more it makes sense. I learned more about fireplaces in this post than I ever knew. It's amazing the dynamics of burning a fireplace successfully. Thank you all for the advice, it's truly appreciated. I'll be trolling your forums for sure. I'll let you guys know how it turns out ass well. Thank you!