Damper Question for DSM1600

MudFlapLip · Post by **MudFlapLip** » Wed. Jan. 22, 2014 1:21 pm

I have a DS1600 in my basement with manual pipe damper installed in the pipe and excellent draft. During this most recent cold wave the temps have been 0 to -5 but where I'm located there is heavy wind along with it. The chain on the flapper is set on the 8th link out giving me good results in terms of temperature variations from the lowest setting to the highest setting. On low the pipe reads 140, stove is 240 with the damper 3/4 closed. On high the pipe reads 335 and the stove is at 600 with the damper 3/4 closed. With the heavy winds I can hear the wind howling through the opening of the flapper. I close the damper all the way and the howling is minimized to an extent. With the damper closed it seems the flames in the firebox are moving slower and are "more controlled". The only issue I've noticed twice now is that on high the stove reads 600 with the damper 3/4 closed. When I fully close the damper and recheck the stove temp an hour or so later, the stove has dropped to 480. I readjust the damper to 3/4 closed and the stove climbs back to its normal high setting of 600. Any explanations for this?
The cold snap we had a few weeks prior to this was worse. I had to actually shorten the chain one link and operate from the 9th link for a few days to get more primary air. The stove wouldn't get past 600 and I needed it to. All along I was combating the closed damper and didn't know why. Yes 600 is the recommended maximum operating temp but as others have posted going slightly above that for short periods is acceptable. Any thoughts or suggestions would be helpful. Stay warm.

Post by **Lightning** » Wed. Jan. 22, 2014 2:03 pm

MudFlapLip wrote:The only issue I've noticed twice now is that on high the stove reads 600 with the damper 3/4 closed. When I fully close the damper and recheck the stove temp an hour or so later, the stove has dropped to 480. I readjust the damper to 3/4 closed and the stove climbs back to its normal high setting of 600. Any explanations for this?

A manometer should show that when the manual damper is closed the negative pressure in the firebox is weakened. Since negative pressure (chimney draft) dictates how much air volume is flowing in thru the combustion air opening, heat output falls. Then when you set the manual damper at 3/4, it allows the negative pressure in the firebox to stregthen giving you the opposite effect; more combustion air volume and heat output increases..

So basically, tweak your manual pipe damper for more heat output...

michaelanthony · Post by **michaelanthony** » Wed. Jan. 22, 2014 2:17 pm

I have a mpd approx a foot and a half before my baro and at the breech of the stove I get 330* and just before the baro I get 170*, and just aft the baro 120*. This is with the mpd closed and my manometer @ -.04,-.06 with high winds near a mile high mountain. My stove is running about 450*-500* and I am getting a ton of heat off the 3ft. of back pipe and the fire is nice and lazy.

MudFlapLip · Post by **MudFlapLip** » Wed. Jan. 22, 2014 3:56 pm

Ok thanks that makes sense. So I guess basically the only way to get the maximum heat out of the stove is to run the damper no more than 3/4 closed? Or adjust the chain to the 9th ball out to get more on the dial. With the damper fully closed on windy days I like knowing I'm not loosing all my heat up the chimney. I guess I'll have to sacrifice some in order to obtain higher temps to keep warm.

lsayre · Post by **lsayre** » Wed. Jan. 22, 2014 3:59 pm

This might be a classic case of where a barometric damper would level things out more effectively than an MPD?

Post by **Lightning** » Wed. Jan. 22, 2014 4:04 pm

It's a bit of misinterpretation that a manual damper "holds heat" in a stove.. I actually challenged this idea on a thread. Some good information here.

Manual Pipe Dampers - A Matter of Perspective

lsayre wrote:This might be a classic case of where a barometric damper would level things out more effectively than an MPD?

I think so..

MudFlapLip · Post by **MudFlapLip** » Wed. Jan. 22, 2014 4:16 pm

Yeah I'm trying not to open the can of worms subject MPD vs. Baro haha. I just want to regulate the excessive draft during high wind conditions with what I have available is all. Maybe a baro would be an option next. It seems a little fine tuning with the damper run at 75% may be the answer for now I guess.

Post by **Lightning** » Wed. Jan. 22, 2014 4:22 pm

MudFlapLip wrote:Yeah I'm trying not to open the can of worms subject MPD vs. Baro haha.

I know right lol, that usually ends in turmoil

... Yeah, just open yer manual a little to get more heat if the highest setting isn't producing for ya..

MudFlapLip · Post by **MudFlapLip** » Wed. Jan. 22, 2014 4:39 pm

Right on thanks lightning.

oliver power · Post by **oliver power** » Wed. Jan. 22, 2014 8:16 pm

What you're doing is smothering your fire by closing the damper. The fire needs to breathe. Opening up the damper a little is letting it breathe.

MudFlapLip · Post by **MudFlapLip** » Wed. Jan. 22, 2014 9:35 pm

Yeah I agree Oliver. The more I read about this that's pretty much exactly what's happening. As Larry suggested a few posts ago I may be installing a baro next season. When the wind blows here it literally sounds like an airplane is landing in my front yard. It was so loud when the last front came through I couldn't sleep all night. It's ridiculous.

Post by **Lightning** » Thu. Jan. 23, 2014 3:33 am

I hate when the wind blows like that.. I have these tall pine trees standing around my house. Makes me nervous, keeps me up all night..