Source of a Carbon Monoxide Leak?

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Teriyakijaccuzi

New Member
Feb 17, 2025
2
Virginia
As the title indicates, I am looking to find the source of a carbon monoxide leak from my wood stove. I'm hoping that you folks may be able to share some thoughts...

This winter I've had my carbon monoxide alarm go off 4 times seemingly at random. A couple of times it was windy out and warmer. Other times it's been cold and still. The only real common link in each occurrence is that it's been when the stove has started cooling down and the coals are burning low.

As a bit of background, I have a Drolet 1800 insert that I've used for the past 5 years, burning all day/ every day during the winter.

I installed it myself with an uninsulated chimney liner in a roughly 20 ft brick chimney. I have a chimney sweep come once a year in the Fall and everything checks out fine every year.

I've had a CO alarm in the room since I installed the stove back in 2019 and this winter is the first time the alarm has ever gone off.

I haven't changed the kind of wood I burn or how I burn it. The only thing that's really changed this year is that I replaced the door gasket back in October. However, the alarm did not start going until January.

Also, of note, is that the brick chimney leaks water during heavy rain in the summer, which drips onto the stove and has caused some surface rust on the stove and where the chimney liner connects to the stove.

Could I have installed the door gasket incorrectly, causing CO to leak out that way? Could moisture have caused a seal at the chimney liner connection of the stove to deteriorate? And then CO leaks out when the fire isn't hot enough for a good strong draft?

I'm really at loss as to why this could be happening.

Thanks in advance for any insights!
 
This sounds like it may be draft reversal. This could be caused by an exhaust fan coming on or a window on a second floor being cracked open. Insulating the liner would help strengthen the draft by keeping the liner warmer.
 
I had considered the possibility of some kind of draft issue.

I have a single story home and dont have anything stronger than a bathroom exhaust fan, which is 4 rooms away from the stove.

I just think it's odd that I've used the stove for 5 winters and never had a CO alarm go off until this year... So I'm not sure why a draft reversal would start out of the blue.