I don't think so the most I've been getting is .06 when it's on 1 with tin foil over the BD. The only time it really needs the BD is when it's starting a fire from nothing. I went all out on the chimney I don't know how I can get anymore?
While it doesn't really matter if the BD is sealed up, or gone entirely, I'd be tempted to think that if it's only getting a slightly high draft at startup, a BD isn't really needed. Of course, you'll want to watch as the temps change with winter, but with your outside stack, you might not see an increase in draft when it gets really cold. I'd love to eliminate the BD if I could, and I threw in some just plain wrong features when I ran my stovepipe, because I already knew I had some excess draft to knock down. It wasn't enough. The BD is always open, and I'm currently working on cobbling up an outside air supply for my BD as I can't stand the notion of it sucking the warmest air in the house (next to the furnace) up the pipe 24-7. I'm not telling anyone to do this, and Lammpa already told
me not to do this, but I'm a big boy, and I'll deal with my mistakes - if it turns out to be one.
I'm not in love with the notion of having any holes in my stove pipe, either, and that's what a BD is. There's going to be situations where that gap around the flap could allow a glowing something to be emitted. I've done what I can to separate anything that could be fuel from my stove, but that's never perfect, and the thought of some spark ending up in a dust-bunny filled crevice somewhere has always troubled me. I'm working to make the outside air attachment something that would contain such sparks as well.
I've already had a bit of a problem with the BD allowing black and brown bits out into my room. I don't know if it was only high winds with the stove off, but I suspect not always. It didn't start until the stove and pipe had dirtied up somewhat, and I cleaned it all a week or two ago, and it isn't doing it again - yet.
FWIW, it was one time only, but this week I had a significant smoke explosion in my Kuuma while I was relighting it from minimal coals. I had put some wood bits, paper, and kindling on the few coals over the grate, and left the ash drawer open to ignite it. Once well lit, I closed the ash drawer intending to let the stove heat up, while I walked away to pick out what I would feed it next. My back was turned, but there was a loud whoomph like a really large log toppling down in the fire box would sound like in the old Clayton, but with that low frequency wave moving through my insides feeling, combined with clanking from the BD. That kind of thing, and a BD, makes me REALLY nervous. No harm done, but it really got my attention!
The original owners of this house had an arrangement where they were stacking about 1/4 cord of wood literally against the side of the old Clayton. I'm sure it helped to make the wood just that extra-crispy dry, but for God's sake NO!
Anyway, through all the grief you've experienced, you might just have what I had hoped for - no need for a heat sucking baro damper!
All that aside, it seems like you've gotten a lot more positive on the Kuuma experience. I'll be really interested to see, as you (I'm assuming here) have a chance to get back to some colder weather with most of the bugs worked out. I know there was a time a month ago, here at least, where I was surprised at how hard I was already working the Kuuma to keep up. The weather eased, and it's been more of an issue of deciding weather to let it go out, or not. It seems like every year during this time, I'm looking at the wood consumption, and the wood supply, thinking that there's no chance of making it to spring, but every year there ends up being plenty left. Maybe it's snow cover on or around the house, or sun angles, or something that makes the difference?? I know we're both hoping we have enough horsepower for the dead of winter.
I appreciate your understanding on my previous post. I couldn't sleep, but wasn't awake, either, and typed some stuff poorly that seemed rather rude. It wasn't intended that way, and I'm sorry! I was going to delete most or all of it, but I see it's been incorporated to a degree, so I just cleaned up what I could. Some of it's probably good to throw around for the next guy to ponder.
Good to see things are going your way - you're certainly earning it!