# New wood stove set off CO alarm. Should I be worried?



## Michael Morgan (Dec 11, 2013)

So I _finally_ got my hearth built, Selkirk chimney, and Jotul F500 (Oslo) installed. Looks great, and the first three break in burns went smoothly. As expected, there was a burnt paint smell and a very faint haze that I wasn't expecting, but I chalked it up to the paint curing. Absolutely no discernible smell of smoke. While I was away the next day, my sister lit the fourth fire and according to her the CO detector in the next room went off right around the 400 degree mark. I only have one, and thinking it might be a fluke, she borrowed the neighbors plug-in and that also went off. For the life of me I cannot find any leaks - everything seems to be sealed tightly and the stove appears to be drafting well. Even if I open the door mid-fire, there's no back-puffing that I can see. I let the stove cool down and ran another fire up to 500 degrees - no CO alarm going off, no smoke detectors going off. I want to leave this running overnight, but my wife is now concerned. Any suggestions as to what could be going on, and what I can do to give us peace of mind? Thanks so much!


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## begreen (Dec 11, 2013)

Sounds normal. You need to get the stove over 500F to completely bake in the paint. And open a window or two. After that you are set to burn.


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## 1750 (Dec 11, 2013)

begreen said:


> Sounds normal. You need to get the stove over 500F to completely bake in the paint. And open a window or two. After that you are set to burn.


Are you suggesting the paint off-gassing triggered the CO detector and that this is normal?  I haven't heard about that happening before.

I guess I would be really reluctant to run the stove until I could be sure this was the case.  It also might have nothing to do with your stove, but I'd want someone who knows more about stoves and CO leaks to take a look at the hvac systems very soon.

Again, if BG is saying this is normal, I am sure that's the case.   I would just want to confirm that this is what he is saying.


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## begreen (Dec 11, 2013)

Maybe wait until the weekend for the first long fires. That way you can check things during the daytime if any alarm goes off again.


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## jdp1152 (Dec 11, 2013)

1750 said:


> Are you suggesting the paint off-gassing triggered the CO detector and that this is normal?  I haven't heard about that happening before.
> 
> I guess I would be really reluctant to run the stove until I could be sure this was the case.  It also might have nothing to do with your stove, but I'd want someone who knows more about stoves and CO leaks to take a look at the hvac systems very soon.
> 
> Again, if BG is saying this is normal, I am sure that's the case.   I would just want to confirm that this is what he is saying.



Breaking in of two inserts never set off a CO2 alarm in my house....and I did both during winter with windows closed and CO2 detectors in each room.  Running an insert on the cool side, particularly if the chimney is on the exterior of the house potentially will not get the unit/flue hot enough to create proper draft and could allow some spillage into the room if the door is open and/or cracked for duration.  If that's the case, I wouldn't worry too much about it provided you get a nice hot fire going before loading her up (or top down fire).  Only way to know for sure is for the thread starter to be there for the next fire and know what the variables are and report back.  I've got some negative pressure in my house and that I'm addressing and overcoming, but a nice hot fire always wins for me.


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## goldfishcastle (Dec 11, 2013)

Was the furnace running when your sister started the stove?   Perhaps the CO alarm was due to this...

"Another source for CO is backdrafting. When ventilation equipment, such as a range-top vent fan, is used in a tightly sealed home, reverse air flow can occur in chimneys and flues. An operating fireplace also can interact with the flue dynamics of other heating appliances. Again, backdrafting may result."

http://www.ext.colostate.edu/pubs/consumer/09939.html


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## 1750 (Dec 11, 2013)

jdp1152 said:


> Breaking in of two inserts never set off a CO2 alarm in my house....and I did both during winter with windows closed and CO2 detectors in each room.  Running an insert on the cool side, particularly if the chimney is on the exterior of the house potentially will not get the unit/flue hot enough to create proper draft and could allow some spillage into the room if the door is open and/or cracked for duration.  If that's the case, I wouldn't worry too much about it provided you get a nice hot fire going before loading her up (or top down fire).  Only way to know for sure is for the thread starter to be there for the next fire and know what the variables are and report back.  I've got some negative pressure in my house and that I'm addressing and overcoming, but a nice hot fire always wins for me.


What you are saying makes sense.   

I just get nervous when people are talking about CO detectors going off and not having a certain explanation for why that is happening.

Thanks.


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## Michael Morgan (Dec 11, 2013)

I was thinking of having a local chimney installer come have a look at my work and see if he can identify any issues. Good idea?

It's hard to identify causes since I wasn't there when she did it. I'm guessing she might have been taking her time with the door open while trying to start it and some smoke could've gotten into the house. Could this have caused it to trigger?

Begreen, I guess I'm a bit confused. Are you saying the off-gases from the paint could've done it? Also, are you saying that if I get up over 500 and can run some long fires during the day with no alarms I should be good to go?

Thanks again for all of the help guys, any detailed explanations are going to go a long way with the significant other. Which makes my life much easier.


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## Cynnergy (Dec 12, 2013)

I definitely think it would be good to keep a very close eye on it and get in an installer to check. You don't want to be messing with CO - it is dangerous for sure.  I personally wouldn't leave it burning overnight for a while.  Maybe I'm just paranoid but CO scares me.

I think CO detectors can go off if a lot of smoke gets in the house, so it could just be that your sister didn't get the fire lit very well and it got a bit smoky, but it could be a symptom of something that needs more attention.  AFAIK the paint fumes do not include CO - it is always stated that they are non-toxic and CO certainly is.

Here's some excellent background reading: http://www.ext.colostate.edu/pubs/consumer/09939.html


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## oconnor (Dec 12, 2013)

Is there another combustion appliance in the house - water heater, furnace etc? It's possible the draw from the stove is causing another unit to vent into the house.


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## Jags (Dec 12, 2013)

Michael Morgan said:


> Begreen, I guess I'm a bit confused. Are you saying the off-gases from the paint could've done it? Also, are you saying that if I get up over 500 and can run some long fires during the day with no alarms I should be good to go?


I am not speaking for BG - but I will throw my hat into the ring.  Yes - if you are still at the point of break in fires (and 400F stove top is STILL in the breaking period) - the off gassing _could_ cause the alarm.  My bet is that you hit it on the head with a new user (your sister) allowing smoke from the startup to enter the home.


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## GeneralBill (Dec 12, 2013)

Michael Morgan said:


> As expected, there was a burnt paint smell and a very faint haze that I wasn't expecting, but I chalked it up to the paint curing. Absolutely no discernible smell of smoke.



I would want to know with certainty what caused that alarm. Maybe the smoke/CO came from backpuffing or reverse air as was suggested. Was it warmish on that day? Some tight homes have issues when other appliances exhaust air at the same time. Once, my wife wanted to clear the bed of coals and put a lot of red hots in the can. No CO alarm, but I could see that happening.

Let us know what you find.


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## Sprinter (Dec 12, 2013)

Is the stove hooked up to outside air (OAK)?  And is the house built tight?

FWIW, I've never had the CO detector go off, even when we had a couple of backpuffs.  Smoke detector, yes, but not CO.


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## Slow1 (Dec 12, 2013)

A couple thoughts -

1) Not knowing where the CO came from would irritate me until figured out - some good theories tossed in this thread, I'd keep a close eye on variables.  Some basic things to think of:
- Any other combustion appliances in the home (gas stove/dryer?, other heating - water?)
- Do you have an attached garage and is it possible someone allowed CO in through there?  I actually had this happen a couple weeks ago.
2) I wouldn't have less than 2 CO alarms and only purchase those that have the display of current/peak readings.  
- At least one on each floor of the house
- One within 10ft of any bedroom door
- One near sources of CO (i.e. basement boiler etc)
3) When/if alarms go off, call the FD (non-emergency number may be good) and, unless you can confidently verify the levels are low (i.e. a couple detectors reading 10-20ppm isn't "rush out into the cold to breath level), move everyone out to fresh air.  IF FD is going to help you out, don't ventilate the house (you are outside anyway) so that it will be easier for them to chase down the source.

CO is not something to be messed with really - silent, odorless, tasteless, colorless.  Consumer grade CO detectors are good - but I would never rely on just one as the potential for failures.  Also remember that these don't last forever, I believe some manufactures recommend replacement every 5 -10 years or so.


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## begreen (Dec 12, 2013)

Was a sealant used at the flue collar?


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## Charles1981 (Dec 12, 2013)

I would freak out with this. I have tested my CO alarms (cheapo china made ones from home depot). 

The only way I got them to set off was putting them directly in front of my exhaust  from either the car or the generator about 1 foot away . Once in the line of the exhaust they went off in about 4-5 seconds. 

If any of them went off in my house I would not be running the stove any time soon...until I figured out why. I would at least purchase 2 more new ones. I have 3 in my house. Upstairs, Downstairs, and our Bedroom.


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## USMC80 (Dec 12, 2013)

I agree with Slow1.  Call you local fire department and have them come over with a detector.   That's exactly what i did and turned out I had a faulty detector and no signs of CO inside


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## madison (Dec 12, 2013)

I believe my detector instructions suggested testing with a cigar or cigarette.

My question and where I would investigate is who and how was the chimney installed?  Into an existing tiled chimney?  Full liner?  Hopefully the chimney is not shared with another appliance.  If this was subcontracted and not done by yourself, immediately have them explain and inspect their work.

If the home has two chimneys close together, you could have a down draft in the second chimney and pulling CO, but I would think that you would probably smell wood smoke as well with this condition.

The only other thought is to examine all potential sources of CO, ie the furnace, hot water heater etc.  We had a dead duck in our furnace chimney one yr and the back pressure from the duck feathers was enough to trip the furnace pressure sensor.  Depending on your other heat sources, an obstructed chimney for you furnace or water heater could be the source, and the new woodstove changed the dynamics of the exhaust of the existing chimney's.

Do not ignore a CO!


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## madison (Dec 12, 2013)

Mike, I just read your thread (https://www.hearth.com/talk/threads...furnace-and-a-wood-stove.115037/#post-1539883)  please tell me you did not share the chimney...

Edit: read another thread where you say you installed double wall thru two floors and out the attic...  I assume you used Class A pipe thru the ceilings etc?
https://www.hearth.com/talk/threads...y-jotul-stove-installation-question-s.117806/

Another Edit: where is the CO meter located is respect to the stove and furnace?  You may wish to consider that the stove is now drawing air from your other chimney for your oil furnace, and that is the source of the CO.

Who inspected the installation?

Also, your wife should be concerned....


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## Heatsource (Dec 12, 2013)

if the stove or chimney is leaking byproducts of combustion they can be traced with a combustible gass sniffer set to sensitive.
I've done this w/leaky pellet vent- they are very accurate IME


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## Michael Morgan (Dec 12, 2013)

Thanks for all of the suggestions and questions. To clear a few things up:

1. I did the installation myself (with a neighbor who has done a couple) and decided NOT to share a flue. So it is all by itself, no way that the furnace is interacting with it.
2. The stove is in the center of the house, which is very old and not well insulated (basically, none).
3. There was no sealant used around the flue collar. Everything sat very tightly, so I did not think it was necessary.
4. There is another combustible appliance, an oil furnace, which was not running and is also on it's own flue.
5. The CO detector is new, along with all smoke detectors, and the CO detector is located about 15 feet from the stove. It does not tell us how much CO is present, it just sounds the alarm.

After hearing all of this, I still feel like it was most likely my sister (a novice) leaving the door open too long early on and letting smoke into the house. But as you all seem to understand, it's a bit scary and not being able to find the source is troublesome.

A few more questions:
1. Should I ask the FD to come over with a detector to try and find leaks?
2. Should I try to replicate what she did by leaving the door open a little too long and see if that triggers the alarm again?
3. I'm happy to install more CO detectors. Any recommendations?

Thanks so much guys, all of the input is very, very appreciated.


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## tfdchief (Dec 12, 2013)

Did the CO detector continue to go off for any length of time?  Was it 4 beeps, pause, 4 beeps?  CO detectors don't clear themselves nearly as fast as smoke detectors so if it didn't continue to go off for some time, or if it did not sound the way I described, it could be a bad detector.  How old is it?  First of all, I agree with some others......don't ignore it and don't go to bed without what you know is a working detector.  Buy a new one if you have to.  Many fire departments will come out and check readings for you.  Their meters are far more sophisticated and will detect very low levels of CO.


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## madison (Dec 12, 2013)

Leaving the wood stove door open would increase the airflow up and out the chimney and IMHO would not exacerbate CO into the home produced by the wood stove.  It COULD possibly increase the draft DOWN the oil furnace chimney - IF the pilot light is light, or the furnace is being used intermittantly and that chimney drafts poorly, there could be a buildup of CO in that chimney which is then pulled into the home by the woodstove.

1.  Should you as the FD to come over - yes, and have them inspect your furnace as well - not just the woodstove.
2.  Should you replicate - NO - Not unless you have a death wish.
3.  Wait for the FD to instruct you what should be done with the meters etc.


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## jdonna (Dec 12, 2013)

http://www.kidde.com/Documents/900-0076.pdf

Maybe read through this link about CO detectors.  They are quite sensitive and particular where you install them.   We had one that would randomly go off and found it to be triggered by a cold air return.  Two other detectors in the same room showed no signs of CO.  

I had a friend in the HVAC business verify that we did not have any issues. 

  CO is not something to mess with.   

Hope you get things figured out over there.


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## JayD (Dec 13, 2013)

Your going to get that hot paint smell every 100 degres that you reach until ya reach 700,  That stank would set mine off to. This also may happen next season at the start of the year, Burnig off dust and crap,  Jay


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## lml999 (Dec 13, 2013)

Michael Morgan said:


> 1. Should I ask the FD to come over with a detector to try and find leaks?



In my experience, your local FD will be delighted to come over and help out...Make sure that you can replicate the alarm while they are there, otherwise it becomes more of a guessing game on their part.


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## jdp1152 (Dec 13, 2013)

USMC80 said:


> I agree with Slow1.  Call you local fire department and have them come over with a detector.   That's exactly what i did and turned out I had a faulty detector and no signs of CO inside



I did this as well. There was an existing one in my basement that went off back when I still burned oil.  Those guys are very cool with household safety and, at least in person, more than willing to stop in.  Gas companies if you think you smell gas, likewise.  Err on the side of caution and feel safe.


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