Manual Pipe Dampers .. How, Why, When

I think lightning's position is that both devices act to decrease draft which I believe to be true. The baro acts automatically while the manual damper must be set and reset if draft changes and constant draft is desired.

There is however a difference in the behaviour of the flue gas when using a manual damper. Flue gas when encountering the restriction of the manual damper will tend to bunch up in front of it and then increase velocity in passing through it where it then encounters the much lower pressure of the full size pipe which causes turbulence. Turbulence both before and after the damper coupled with the slowing gas will have a baffle effect beyond just slowing the gas. This turbulence could effect the heat exchange of the stove and account for the belief that it holds the heat in.

To prove it one way or another would take some careful measurement.

Damn Kevin, I thought the proof was always in the pudding???

Heh heh Fred, no the proof is elusive. I like a good debate and had to much time on my hands this day. I an stuck in a catastrophe created by 1 inch of snow! Whodathunkit!!! Anyhoo, all in good fun. Use whatever works for you and stay safe buddy.

Kevin

You too Kevin, I didn't see anything about your area, but I know all this is raisin hell in the Atlanta area

LOL, they got 2 to 3 inches and we only got 1. But you should have seen it!!! It took me 4 hours to go about 3 miles yesterday. It is total gridlock man. I cannot put it all on the southern drivers. The conditions were brutal for anyone. Yes, I could go where I wanted when I wanted. But these are people in cars that have no business being on the road. No inspection here you know. Bald tires, bad brakes, etc. It was a circus. And to be further honest, most of these people would not have gone out in it but the weather people called for a few flurries. They went to work, got out at noon or so, and the highways were just jammed with them trying to all go in the same direction. I could have driven INTO Chattanooga in about 10 minutes. But getting out was a biaaatch.
Overall, quite the experience and one that was not necessary for many reasons.

Kevin

Lightning wrote: I wasn't referring to you.. But if you wanna throw stones from over there that's ok with me..

Lighting - my mistake - in the words of Lily Tomlin "Never Mind"

dj

I use both I have a SS chimny that will draft any stove out of control wood or coal. My sf250 would suck so much air when it was hot it would wissle with the bero wide open. I run about 1/2 mpd bero takes care of the rest

This I like Chevy vs. Ford. I believe there are times for one and times for the other. One thing I find funny is that when people who use baro's describe how mpd's work they make it sound like we're all sitting around with nothing to do constantly adjusting the mpd, married to it. They can't help it...they feel their baro is better so even the description of how the mpd's work is always described as being so much work and constant adjustments. I set mine once the stove is running and never have to touch it. If your stove has good gaskets the amount of airflow is determined by the air under and over fire intakes. Even though over fire air is not near what under fire air is, it's still intake air. I believe both work and have their place. I want to make sure that people realize they don't need constant adjustment.

BPatrick wrote:This I like Chevy vs. Ford. I believe there are times for one and times for the other. One thing I find funny is that when people who use baro's describe how mpd's work they make it sound like we're all sitting around with nothing to do constantly adjusting the mpd, married to it. They can't help it...they feel their baro is better so even the description of how the mpd's work is always described as being so much work and constant adjustments. I set mine once the stove is running and never have to touch it. If your stove has good gaskets the amount of airflow is determined by the air under and over fire intakes. Even though over fire air is not near what under fire air is, it's still intake air. I believe both work and have their place. I want to make sure that people realize they don't need constant adjustment.

but but but... whats the difference? which is better? (inside joke )

BPatrick wrote:... the mpd's work is always described as being so much work and constant adjustments.

Every winter hundreds of MPD-using coal burners collapse from nervous exhaustion, trying to get it just right. Don't be a statistic! Order your baro today. We have them available for immediate shipment starting at $650 and up.

During the COLD, I keep my MPD 3/4 closed except when tending every 12 hrs, then back to 3/4 closed--during the cuff months like now, she stays open. I think I just got more exhausted typing this. PS--that constant adjusting is complete nonsense

freetown fred wrote:PS--that constant adjusting is complete nonsense

You've just been lucky..

That ain't luck Lee, that's skill or knowin when to leave things alone. The MPD don't do anything except prevent down draft blitzes & keep a lil more heat IN the stove.

I haven't added much to this thread, since I started it.

I've been using the MPD, exclusively for 7 years, now, without a glitch. I open it to stoke the fire and close it after shutting the door ... "most of the time". I keep it open, when starting the fire. Occasionally, I forget to close the MPD! What I've observed: if I forget to close the MPD, I'll notice the house isn't maintaining the thermostat temperature (house temp. drops). I take a look and find that I've forgotten to close the MPD. This morning, I went down stairs to tend the stove and discovered, it was all but burned out. ... I'd left the MPD open last night, after I tended the stove. The house hadn't been overly hot all night, nor this morning. It would be unusual for the fire to be out in the morning, especially in this milder weather.

My conclusion: Operating the MPD in the proper manner, allows the stove to heat the house much better and burns much less coal. It makes my whole system considerably more efficient and stable!

And I don't spend any time trying to "fine tune" the MPD, as the draft is automatically controlled by my room thermostat controlled stove damper.

Just my observations and conclusions.

dlj wrote: Lighting - my mistake - in the words of Lily Tomlin "Never Mind"

dj

Gilda Radner...

Dan