MSG: about dampers, please

[precaud]

Given the F400's reputation for needing more draft than other Jotuls, I was surprised, and intrigued, when I read your posts about BG's Castine install, and your recommendation that he might need an inline damper.

Can you describe for us what conditions/symptoms you're mindful of when you advise a damper be installed?

The way I see it, with modern stoves, a damper primarily affects the "always-on" secondary air systems which most of these stoves have, making their use less straightforward than in early days. But I'd love to hear what your experience has taught you about it.

 

[MountainStoveGuy]

I was only basing that on his chimney. He has a very tall chimney for his elevation. 19' typically would call for a inline damper to help slow the flue gas from escaping and not getting burned. The f400 is not for aplications where draft will be challenging, like lots of elbows, shorter then recommended chimney hight, long horizontal runs, basements installs and the like. Given that BG has such a tall chimney, it was my guess once he gets the downslope out of his 90* or T on the back, he will have strong draft. Lots of things play into the equation, like negative pressure that exists in the home and the amount of exposed pipe on the exterior. Lots of factors affect draft, but assuming he has a normal install, i think he will want a damper at some point. Time will tell.

 

[begreen]

Only burning in the low 50's outside so far. I ended up having to fix the downslope. The spa repairman they sent out the second time was not much help. Now I have a nice upslope. That cured smoke coming out on startup and has also cleared the glass somewhat. So far the Castine is very well manored and not showing signs of overdraft. It seems to like a strong draft. We'll see how it behaves at 35-40, but for now it's running without a stack damper and is a joy to operate.

Seems each stove is unique. Our 3CB install had about 4ft. less stack and wanted a stack damper.