Carbon Monoxide after fire goes out

[Rich L]

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.

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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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.

 

[BrotherBart]

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.

 

[Rich L]

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.

 

[PWash]

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.

 

[Squisher]

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.

 

[goldenheart]

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.

 

[Squisher]

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.

 

[revdocjim]

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.

 

[Squisher]

Which is what I'm interested in learning about.

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

 

[fire_man]

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.

 

[sdmws6]

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.

 

[begreen]

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

 

[Corey]

... 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!

 

[electrathon]

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.

 

[Smoked]

...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!

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

 

[Rich L]

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.

 

[Squisher]

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.

 

[Rich L]

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.

 

[Squisher]

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?

 

[Chettt]

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.

 

[madison]

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

 

[Rich L]

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.

 

[Squisher]

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.

 

[Rich L]

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?

 

[Squisher]

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