# Carbon Monoxide after fire goes out



## sdmws6 (Nov 24, 2015)

Hi everyone,

I have a Dutchwest Majestic Cat Stove from 1996 and it's been burning great. However, every time the fire dies out, my CO alarms go off in the room. I've tried sealing everything and re-gasketed the entire unit. It's very frustrating and I'm not sure how to prevent it. My chimney is an exterior setup that skirts up the side of the house (pics included) so cold-chimney syndrome might be at play here. I can see the little red embers still glowing inside the stove and I'm afraid the gasses aren't rising up the chimney. Has anyone else experienced this problem or know of a fix? Thanks.


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## kennyp2339 (Nov 24, 2015)

Maybe add another section of chimney pipe to increase your total run, get rid of the 90 deg bend on the black pipe and replace it with (2) 45 deg pipes.


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## fatjay (Nov 24, 2015)

Is your chimney double wall insulated? Sounds like when the fire gets cool enough, all it takes is a gust of wind to blow the cold air down, the cool air feeds the fire, and blows the byproduct of the burning embers into the house. I get this from time to time, so I try to keep it hot, or shut it down entirely.


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## sdmws6 (Nov 24, 2015)

fatjay said:


> Is your chimney double wall insulated? Sounds like when the fire gets cool enough, all it takes is a gust of wind to blow the cold air down, the cool air feeds the fire, and blows the byproduct of the burning embers into the house. I get this from time to time, so I try to keep it hot, or shut it down entirely.


Yes, it's a Selkirk Super-Pro double wall. How can I shut it down entirely?

Another instance is when the house cools down (around 4 in the morning) and the T-stat kicks the heat on, the central air unit sucks air from the center of the house. It's sucking air from the wood stove and spreading the CO all throughout the house. I guess wood stoves and central air units don't mix?


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## kennyp2339 (Nov 24, 2015)

sdmws6 said:


> I guess wood stoves and central air units don't mix?


 They can exist or co exist, you need to check and see if you stove has an OAK built into it.


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## fatjay (Nov 24, 2015)

I know many people with stoves and central air, who use the central air pump to transfer heat throughout the house.

If you close off all the vents on the chimney it should be pretty much air tight, otherwise you'd be bleeding heat any time you didn't use it in the winter.


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## velvetfoot (Nov 24, 2015)

If you have downdraft even while the stove is warm with red coals, that really is not a good sign.
I wonder if you could keep the chimney warmer by building an insulated chase around it?


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## fatjay (Nov 24, 2015)

Generally you wouldn't have a downdraft while warm, but my buddy has that issue when it gets windy. He has an extremely long chimney as well.


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## begreen (Nov 24, 2015)

Basement stove, yes? It could be that is a negative pressure zone or near-negative. Is something kicking on that could reverse draft like a gas hw heater or a boiler/furnace?


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## electrathon (Nov 24, 2015)

Keep in mind that it is likely not just your furnace causing a downdraft on the wood stove.  Your stove is likely causing a downdraft on your furnace and water heater, unless you have electric heat and electric hot water.  Can also be caused by a gas dryer or a bathroom/cook stove fan.


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## sdmws6 (Nov 25, 2015)

Thanks everybody for all your input!
The stovepipe is cold by the time the CO alarm starts going off, yet there are traces of red embers still left. I now have to make sure the central air handler for the furnace is turned off, both on initial startup of the fire and when the fire starts dying down. Otherwise it'll suck air upstairs from everywhere. The furnace and blower are located in the attic of our bi-level home and the wood stove is downstairs. I have read about negative/positive pressure zones and that very well may be the case. I've done toilet paper tests and it's shown that air is getting sucked into the house through downstairs windows, and pushed outside in upstairs windows. Neutral is between 4ft and 5ft up from the ground on the second floor.
All of our appliances are electric, so I wouldn't think there would be an issue there. I made sure that no blowers throughout the house turn on in the morning, so I don't think they are associated with the CO issue.
Fatjay, I have no vents to close on the chimney. From the stove, the pipe goes up, then a 90 into the wall, into a tee, then up the house. Should there have been some sort of shut-off valve installed?
Kennyp2339, there is no outside air kit for this model stove. The non-cat stove has one, however.
Velvetfoot, I've thought of that, but that's a little over-budget for us at the moment. That probably is the best solution though, before installing a chimney inside the home.

I have noticed when I leave a downstairs window open overnight, the CO alarms don't go off in the morning. The resolution seems to be to provide make-up air downstairs. However, it's freezing in the morning when I leave a window open and completely nullifies the advantages of having the wood stove... HELP!


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## begreen (Nov 25, 2015)

A clothes dryer, kitchen and bath exhaust fans can also exacerbate negative pressure. In the least the stove needs an outside air kit. If that doesn't fix things then consider moving the stove upstairs.


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## mellow (Nov 25, 2015)

Isn't that singlewall pipe going to the thimble?  I would upgrade that to doublewall to hold the heat in and hopefully will not have the draft reverse as easily.

You could also install a heat recovery ventilator so the fresh air isn't as cold coming in.


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## sdmws6 (Nov 25, 2015)

Mellow, yes it's single wall going into class A through the thimble. I can try switching over to double wall, but I'm afraid to spend the money when I'm not sure that little bit of extra insulation will make a difference. Right when the chimney exits out through the wall, it's completely exposed to the cold air outside, which is where most of the chimney is.


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## rwhite (Nov 25, 2015)

Just a thought to tie into begreen idea of adding an OAK. Is it possible that when the fire is burning active it can draw enough air from other areas of the home and not set off the alarm, as the fire cools it is not drawing adequate air and the concentration of CO increases? It would be my guess that an OAK is the solution.


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## rwhite (Nov 26, 2015)

Another thing that may help folks diagnose your problem is a layout of the basement. How big of a room does  the stove sit in? Where all the other CO detectors located and is the one in the basement the only one going off?


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## sdmws6 (Nov 26, 2015)

rwhite, I think you're absolutely right. Once the fire dies, the CO starts pouring out the air intakes of the stove due to the cold chimney/negative pressure. Unfortunately, there is no OAK for my model; only the non-cat model. Attached is a basic layout of the home. If the furnace turns on in the morning, the upstairs CO detectors go off around 4-5am, both in the hall way upstairs and the bedrooms. The lower one only goes off if the furnace is off, around 8-9am. We do not load any more wood after 11pm. What happens is the furnace sucks air from the intake in the hallway and dumps heat and CO into the three bedrooms upstairs first along with the living room/kitchen/dining room (because of the proximity of the bedrooms).
Again, thank you everybody thus far.


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## fbelec (Nov 26, 2015)

i would revisit the chimney height. does this happen every night or every once in a while? the chimney cap from the pictures looks to low. it's suppose to be 2 feet higher than the roof within 10 feet. sometimes if the wind even small wind blows across the roof it can hit the cap easy and make a downdraft


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## sdmws6 (Nov 26, 2015)

fbelec, I remember the top being pretty high when I was last up there, but I will take some measurements and verify. Thanks. I found this site and took a photo of it, and describes exactly what I'm experiencing. Last night I had the fire die down overnight and left a window open... No CO alarm. But, it was FREEZING downstairs. It really is a shame that's what I have to do.


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## Smoked (Nov 26, 2015)

Can you figure out where the air intake on the stove is and maybe fabricate something to add an adapter to intake outside air?  Or, contact  the manufacturer and see if there is something they can recommend as a retrofit?


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## begreen (Nov 27, 2015)

sdmws6 said:


> rwhite, I think you're absolutely right. Once the fire dies, the CO starts pouring out the air intakes of the stove due to the cold chimney/negative pressure. Unfortunately, there is no OAK for my model; only the non-cat model. Attached is a basic layout of the home. If the furnace turns on in the morning, the upstairs CO detectors go off around 4-5am, both in the hall way upstairs and the bedrooms. The lower one only goes off if the furnace is off, around 8-9am. We do not load any more wood after 11pm. What happens is the furnace sucks air from the intake in the hallway and dumps heat and CO into the three bedrooms upstairs first along with the living room/kitchen/dining room (because of the proximity of the bedrooms).
> Again, thank you everybody thus far.


I would not burn in this stove under this condition. The CO detectors are warning you of a dangerous situation. If you love the stove move it upstairs. Or consider replacing it with one that has an outside air connection. Or figure out where it's air intakes are and fabricate an air intake manifold that you can connect a fresh air supply to.


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## Heatsource (Nov 27, 2015)

added chimney height will not fix a stack effect problem
your draft is initiated where the pipe passes thru the building envelope.

if no OAK is avail maybe consider a passive air supply near the stove


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## revdocjim (Nov 27, 2015)

I agree that a retro-fitted OAK system of some sort will probably be your cheapest alternative. There are probably members here who have designed such things for stoves that don't have a ready made kit.


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## mellow (Nov 27, 2015)

mellow said:


> You could also install a heat recovery ventilator so the fresh air isn't as cold coming in.



Look into the HRV or ERV systems out there.

http://www.broan.com/products/serie...-systems-d5467c6d-6245-43b0-8f04-3447f6f4b771


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## Mattawan (Nov 27, 2015)

Begreen makes a critical point about negative draft and this can occur with wood stoves as well as with pellet stoves.  Fortunately I have a short exit vent on my pellet stoves but a friend encounters negative draft with a basement wood stove which has a long vertical insulated pipe.  Al he can do to counter it is to open a basement window a bit.


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## Rich L (Nov 28, 2015)

Mattawan said:


> Begreen makes a critical point about negative draft and this can occur with wood stoves as well as with pellet stoves.  Fortunately I have a short exit vent on my pellet stoves but a friend encounters negative draft with a basement wood stove which has a long vertical insulated pipe.  Al he can do to counter it is to open a basement window a bit.





sdmws6 said:


> Hi everyone,
> 
> I have a Dutchwest Majestic Cat Stove from 1996 and it's been burning great. However, every time the fire dies out, my CO alarms go off in the room. I've tried sealing everything and re-gasketed the entire unit. It's very frustrating and I'm not sure how to prevent it. My chimney is an exterior setup that skirts up the side of the house (pics included) so cold-chimney syndrome might be at play here. I can see the little red embers still glowing inside the stove and I'm afraid the gasses aren't rising up the chimney. Has anyone else experienced this problem or know of a fix? Thanks.
> View attachment 167828
> View attachment 167829


  I think a longer burning stove will stop the problem.One that will heat all night with enough heat to maintain an updraft till morning at which time it can be reloaded and keep the heating process going.This means running the stove 24-7.


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## BrotherBart (Nov 28, 2015)

Rich L said:


> I think a longer burning stove will stop the problem.One that will heat all night with enough heat to maintain an updraft till morning at which time it can be reloaded and keep the heating process going.This means running the stove 24-7.



Well, it is gonna burn down sometime and here comes the CO again.


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## Rich L (Nov 28, 2015)

BrotherBart said:


> Well, it is gonna burn down sometime and here comes the CO again.


I start my basement stove which is a huge stove and maintains a updraft for 14hrs.which is more than enough time for a reload.The soapstone stays warm enough to maintain the updraft even when the coals are low..That's how I deal with my downdraft situation.Burn 24-7.


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## PWash (Nov 28, 2015)

You might try opening the stove's intake draft towards the end of the burn?  It may help burn off the embers quicker and maintain more heat during that time vs a long, slow, cold smoldering of the embers.


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## Squisher (Nov 28, 2015)

Rich L said:


> I start my basement stove which is a huge stove and maintains a updraft for 14hrs.which is more than enough time for a reload.The soapstone stays warm enough to maintain the updraft even when the coals are low..That's how I deal with my downdraft situation.Burn 24-7.




So how do you deal with it at the end of the season or in shoulder seasons?  

Burning 24/7 is not the solution to this safety issue. Besides most people don't want to/can't burn 24/7.  During warmer temps I'm certainly not going to burn 24/7 but in fall and spring I'm not into not having a fire to take the chill off that I can just let go out overnight.


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## goldenheart (Nov 28, 2015)

Squisher said:


> a fire to take the chill off that I can just let go out overnight.



After a while you will get used to when and how much you can load the stove to have the heat you need and have it end near when you want. I burn niels and they have coals that seem to burn low and slow forever so I will only add regular splits after 5:30pm. And then once I am nearing the end, I turn the fan off/move the ecofan off the stove, and I will consolidate all the coals in a pile and add a chunk/end piece on top. I turn the air up and it burns a really small fast hot fire to burn it down while heating things up to maintain draft. If I misjudged, I just repeat it with a second reconsolidation and another chunk. But, I do have a really short interior chimney, so what works for me isn't going to work in all situations.


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## Squisher (Nov 28, 2015)

I'm not sure why you quoted me on that. I was talking about letting a fire go out overnight in the shoulder seasons. No offense but I don't have to tend my fire six times and rake and adjust fans and this and that. I just make some coals and let it burn out instead of setting it up for a overnight burn. 

The point of my post was not to derail this thread into a discussion of how to build a fire to go out. It was an attempt to help get it back on track so the OP can find a safe solution to avoiding Carbon monoxide backdraft.


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## revdocjim (Nov 29, 2015)

Lots of good info here, based on tons of experience and knowledge. Nevertheless, telling the OP he/she needs a new stove or needs to move it to another location in the house doesn't seem all that practical. Perhaps some folks can afford to switch out stoves or do major installs on a whim but for most of us that isn't very realistic. My guess is that this user will appreciate suggestions for affordable work arounds for a potentially dangerous problem.


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## Squisher (Nov 29, 2015)

Which is what I'm interested in learning about. 

If "just keeping the fire burning" is. The solution I'd be surprised.


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## fire_man (Nov 29, 2015)

I agree with the posts suggesting  a fabricated oak. It's the cheapest and probably most effective solution. I would even consider adapting something temporarily to a window so you don't have to commit to a hole in the wall in case it does not work.


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## sdmws6 (Nov 30, 2015)

begreen said:


> I would not burn in this stove under this condition. The CO detectors are warning you of a dangerous situation. If you love the stove move it upstairs. Or consider replacing it with one that has an outside air connection. Or figure out where it's air intakes are and fabricate an air intake manifold that you can connect a fresh air supply to.


It's tough to move the system upstairs. I do agree though, it's not an easy fix. I'm not burning 24/7 because I feel someone must be home to tend the stove in case anything happens, as with any appliance.
Revdocjim makes a good point though; with enough time and money, I can do anything and make the perfect setup. However, I'd rather not use the stove entirely if I couldn't find a safe alternative. There is good news though. I've been running the wood stove off and on the past couple of days and I have not had any CO issues by leaving a downstairs window open. I know, I've said this before, but I've been experimenting with various amounts to open the window. I've reached a conclusion that I only need to have it cracked open 1.5in for there to be no alarms going off, and yet the downstairs still remains warm in the morning. It's enough to supply fresh air and reduce the negative pressure and yet keep the downstairs warm.
I've also looked into fabbing up an OAK. The intakes are right on the lower front, on each side of the glass door. There are a few problems though, one being the intake ports are tightly stuffed on the unit between the intricate trim. I think my best fix without demolishing the house would be to open a hole in the wall as low to the ground as possible, dropping the neutral pressure zone as low as possible, and supply the home and stove with outside air, passively. I saw Heatsource mentioned this, thanks. I found a Residential Air Supply Ventilator on Condar's website I think will work wonders.
I'm so appreciative of everyone's suggestions so far. Thanks again! What do you think of some sort of passive vent system low and near the stove? The window I open is on the other side of the house and roughly 4ft up the wall, and it seems to be working really well.


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## begreen (Nov 30, 2015)

Another option would be to replace the stove with one that has an OAK connection and breathes easily.


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## Corey (Nov 30, 2015)

sdmws6 said:


> ... I've done toilet paper tests and it's shown that air is getting sucked into the house through downstairs windows, and pushed outside in upstairs windows. Neutral is between 4ft and 5ft up from the ground on the second floor. ...



...and when the windows are closed, air is getting sucked through the stove downstairs and moves up through the house, heading for those upstairs windows.

You can attack this in several ways, but I don't think the chimney is a huge problem.

1)  Stop / reduce any chances for air to exit on the upper levels...seal windows, doors, attic access, attic fans, air returns leading to the attic.  This will help reduce the back-pull on the stove.

2) Break any remaining 'stack effect' in the house if possible.  Close doors you don't need open - especially ones leading up / out of the stove room.  Though if you have an option to open doors on a lower level, that may help too...you might get air flow coming in from other rooms to dilute the stove heat and reduce the stack effect.

3)  Mix the air better in the stove room.  If the entire room is ~70ºF, then that air is less likely to rise out of the room and create an internal 'stack effect' than if you had 100ºF air at the ceiling and 65ºF air at the floor.  Even a ceiling fan on low may be enough to break the 'hot air rising' cycle.

4)  "Stuff" the stove room with positive pressure.  Even a small fan setting outside the stove room door could create a bit of positive pressure and stop the back flow of the flue pipe.  If you can aim the fan at the top of the door, that would be even better as that is where the hot air would typically like to exit. (aiming at the bottom or floor, may make things a bit worse.

Good luck and stay safe!


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## electrathon (Nov 30, 2015)

So looking at the front of your stove, I believe I see the air inlets at the bottom left and bottom right. Looks like square openings.  What I see it looks like you could fab up a double pipe coming under the stove and up, to a squared off flange on each side. This would look sort of like a header on a car.   Painted black it would blend right in with the stove and you could use a dryer hose to someplace you could drill a hole through the wall.  A day's work with a little sheet Amal and exhaust pope and you would have a potential life safety issue fixed.


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## Smoked (Nov 30, 2015)

Corey said:


> ...and when the windows are closed, air is getting sucked through the stove downstairs and moves up through the house, heading for those upstairs windows.
> 
> You can attack this in several ways, but I don't think the chimney is a huge problem.
> 
> ...


Thanks for all of this added info.  I had a failed start in my new basement install that resulted in smoke in the basement.  I only used part a of a firestarter and kindling and it never really lit anything so there was never any heat in the chimney.  Had to burn some paper to get things going in the right direction and was normal after that but it got my attention because I have a great draft in my living room install and would have figured would have even more with 8 more feet on the stack but maybe not with this leaky house.  I never viewed this kind of issue as a whole house thing


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## Rich L (Dec 15, 2015)

Squisher said:


> So how do you deal with it at the end of the season or in shoulder seasons?
> 
> Burning 24/7 is not the solution to this safety issue. Besides most people don't want to/can't burn 24/7.  During warmer temps I'm certainly not going to burn 24/7 but in fall and spring I'm not into not having a fire to take the chill off that I can just let go out overnight.


I don't need to operate the basement stove during the shoulder seasons only when it's in the single digits and below.When not in use no threat of carbon .monoxide.


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## Squisher (Dec 15, 2015)

Rich L said:


> I don't need to operate the basement stove during the shoulder seasons only when it's in the single digits and below.When not in use no threat of carbon .monoxide.



So you don't burn it 24/7 then correct?  So whether it's shoulder season burning or just to help out during the really cold temps sooner or later it's going out and if you're getting a backflow of CO that's setting off an alarm. That's not good.


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## Rich L (Dec 20, 2015)

Squisher said:


> So you don't burn it 24/7 then correct?  So whether it's shoulder season burning or just to help out during the really cold temps sooner or later it's going out and if you're getting a backflow of CO that's setting off an alarm. That's not good.


I burn 24/7 when it's going.When it's not going there are no coals going to give off CO thus none of my alarms are going off.When the stove does get down to the coaling stage the stone absorbs enough heat that when the coals burn out the stove is still emitting enough heat  to continue the updraft well after the coals are extinguished.


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## Squisher (Dec 20, 2015)

So what you're really saying is that you have no issue with CO?  So how is how you operate your stove relevant to the OP who does have an issue with CO?


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## Chettt (Dec 20, 2015)

You are smart to have CO detectors, so I'm sure you realise how serious this is. In your case I would turn off the forced air furnace at night and use an electric heater or electric blankets or not use the wood stove.


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## madison (Dec 21, 2015)

One thought, are you entirely sure that the stove is the source of the CO?  Could it be your furnace or hot water heater?

Many years ago, we had pretty much the exact same scenario.  Newly installed basement wood insert, and CO levels jump up after the fire died down.  Turned out it was a dead duck that had fallen down our masonry chimney that our Nat Gas furnace and water heater where connected.  We investigated for days trying to figure out the issue, moving the CO detector around the house, and eventually calling the HVAC people who verified and subsequently diagnosed and repaired the issue... removed the wood duck from the bottom of the masonry chimney.

Don't mess with CO, get it figured out and repaired by a professional


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## Rich L (Dec 22, 2015)

Squisher said:


> So what you're really saying is that you have no issue with CO?  So how is how you operate your stove relevant to the OP who does have an issue with CO?


I did have his problem before I got a large soapstone stove.That's how I overcame my problem.


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## Squisher (Dec 22, 2015)

I'm starting to feel like a dog chasing its tail in this thread. I've had two different stoves over a period of five years in my current house and a third different stove in my old house for nearly 10 years and I've never heard a chirp out of my CO detectors or my smoke detectors except while testing them. CO alarms shouldn't be going off if you let a fire burn out overnight.


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## Rich L (Dec 22, 2015)

Squisher said:


> I'm starting to feel like a dog chasing its tail in this thread. I've had two different stoves over a period of five years in my current house and a third different stove in my old house for nearly 10 years and I've never heard a chirp out of my CO detectors or my smoke detectors except while testing them. CO alarms shouldn't be going off if you let a fire burn out overnight.


My early experience with a smaller stove was when the coaling stage was at a low level the stove didn't emit enough heat to maintain an updraft.The downdraft kicks in and the emissions from the remaining coals came into the basement then the alarm would triggerRemember my basement has the negative pressure working against me.My stove on the first floor doesn't have the problem when it burns out.I wonder how our original poster is doing?


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## Squisher (Dec 22, 2015)

Yah I wonder too. I've been fortunate to have never experienced downdraft issues.


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## Rich L (Dec 22, 2015)

Squisher said:


> Yah I wonder too. I've been fortunate to have never experienced downdraft issues.


 Is your stove in the basement?


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## Squisher (Dec 22, 2015)

Yup. Interior masonry chimney. Both times. So maybe the bricks help the chimney hold heat long enough to maintain the draft until the fires right out?  I let coals idle for a looooooong time sometimes. Like today, easily 13hrs out of some silver maple and still a hot bed of coals I could rake up and ignite large splits no problemo and no CO.  I also have had in both homes a forced air natural gas furnace in the basement as well that can run at the same time if I desire with no issues.


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## Rich L (Dec 22, 2015)

Squisher said:


> Yup. Interior masonry chimney. Both times. So maybe the bricks help the chimney hold heat long enough to maintain the draft until the fires right out?  I let coals idle for a looooooong time sometimes. Like today, easily 13hrs out of some silver maple and still a hot bed of coals I could rake up and ignite large splits no problemo and no CO.  I also have had in both homes a forced air natural gas furnace in the basement as well that can run at the same time if I desire with no issues.


 Sir you are in deed fortunate.Take Care.


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## Squisher (Dec 22, 2015)

Thanks, you as well. I'm thankful that I haven't experienced any draft issues like I read so much about here. Currently I'm about 23' to stovetop through that interior masonry chimney and I find it pulls just right for my current stove. 

I am finding that this 'hobby' of wood burning is starting to consume me and I'm just becoming more and more curious about the how's and whys.


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