EPA stove key damper needed?

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Jun 1, 2021
I have ordered an Osburn 3300 and have not experience newer stoves as i am comibg from an old Defiant. I will be picking up the new stove in the next couple of weeks and will be using 22 guage single wall connector pipe. I have approx 25' of masonry chimney feom the connector pipe to the cap. I have never had an issue with draft and if not careful with the Defiant it could easily run wild is minutes without closing the bypass damper. Thag said, with a newer stove, do folks experience issues with stoves running out of control with only a single air control? I know alot of stoves do no recommend stove pipe key dampers, but would you recommend putting one in during install rather than pulling the connector after the fact. Is tbis an issue i should be concerned about? Thoughts on key damper install "just in case" or am I overthinking it?


Minister of Fire
Nov 17, 2019
Long Island NY
You could add one to be sure, but it's not a lot of work to add one later. And if you don't go straight up (but have a horizontal section thru the wall to the chimney), your effective length drops so it's not 25'-like anymore.
I have 27' and have no damper. And it runs fine (minimum 15' required if no elbows and horizontal section; I do have a 2' horizontal run and thus 2 elbows)

I'd run with it and see if you need one rather than adding one now.


Minister of Fire
Different stoves have different characteristics. Some will need it, some won't. Add one later if you do.


Minister of Fire
Dec 28, 2006
Mt. Rainier Foothills, WA
I ran for years without one on my noncat epa stove with19’ of vertical stack. I added it last year and am very happy with it. They’re cheap and easy to install into single wall.

I like to use it for better control and higher efficiency by reducing draft strength to minimum spec during burns.

D. Hermit

Feeling the Heat
Nov 21, 2020
NeK Vermont
I keep one on all my stoves just in case its just another route to take the fire down a bit if it starts to run away on you


Minister of Fire
Dec 28, 2006
Mt. Rainier Foothills, WA
I verified this year that a sooteater chimney cleaning brush head goes right past a key damper.