Manual pipe dampers .. how, why, when

My stove has a 4.75" exhaust with a manual damper, as equipped by the factory "Haas & Sohn".
The damper consists of a cast iron flange with a cast disc loosely fitted to the throat. The disc
has a 25% cutout and perhaps 1/8" or so around its periphery to allow for the passage of flue gases
even in the "full-closed" position. Additionally I have a 5" barometric damper just downstream from the manual damper and immediately before a 5" to 6" adapter then to the SS chimney insert...to a 6"x9' inch tiled masonry flue, internal to the house. The chimney rises approximately 25'...My stove fits nicely on the existing hearth with an apron.

I have settled upon running the stove with the manual damper closed and the barometric damper adjusted to .05" water
(according to the Dwyer Magnahelic Gauge) this seems to give the most controlled burn with the good heat retention.
I was surprised to find that the stove ran better with the manual damper closed.


Bob

OK I just read every post here and still have questions.

I'm getting a Harman SF-150 and one of the most recent posts said that with wood it will not last all night?? Why not? Every stove Ihave had since I was a kid lasted all night and all but one used a MPD - just wondering why.

So, in the spring and fall when I'm burning wood I should use a MPD to control the fire and not over-fire the stove? then come winter and switching to coal use the baro?

I do not know the draft of the chimney, but when I use my Harman exception wood stove and do not close the damper (built in) the stove would probably melt. I could easily hit stack temps over 900 within 10 minutes - I'm not kidding did that once and it cost me $500 in new parts for the stove. I forgot it while I was getting the kids on the bus.

I was planning to use a MPD for wood burning, but now I'm not sure.

So what do I need??????? I'm so confused now.

I do have 2 CO's and will add more. 1 in each of the kids rooms since their rooms are right above the stove.

Hi HanSoSlow,
When I had my gibralter I alway used a baro(but I only ever burned coal), when I got my new DS Machine hand fed the factory told me to use a MPD. This was new to me so I asked some questions. Now what I am gonna say is what the maker of my stove reccomends, each manufacture is differant so check your owners manual. DS Machine said they use the MPD and it works extremely well. he claimed you don't need that much air flow out with coal and once the fire was going, and after refueling and the gasses burned off to close it completely. Even when it is closed it is not really closed with the holes in the plate and the gap around the side. He said unless people have a manometer they normally don't set up a baro well enough and lose heat up the chimney. That is another point if you don't know your dratf you really need a manometer, to set up a baro properly. I asked him if I could run both and he said that is the best(now bear in mind this is for there stove again). So that is what I did. I have the stove, mpd, baro, then up the chimney. I must say it works extremely well I can feel more heat when the MPD is closed. I got my stove at the end of the season, so I was not really burning it to hot, more of a low fire, and after reading all the posts in this section I thought I am going to do a little experiment. So now I have a test port before the baro and one before the MPD. Out door temps were in the high 50's I checked my draft before the baro (with the mpd open and closed made a negligable differance) and it was -.06, Now I checked it before the the MPD and it was still -.06. This was interersting. This went with what they said at DS Machine. Now Like I said that was on a lower fire, this comming winter when it is really cranking I will retest and repost my results, I expect with the larger fire and more combustion gases comming off there may be a slight drop, but I doubt it will be much. The baro keeps your draft constant which is really nice, and the MPD keeps heat in the fire box. So I guess now I am for having both of them if your manufacture alows. If you want to burn wood then wire the baro shut until you are ready for coal. The thing with the baro is if you have a chimney fire it will open more and add more fuel to the fire. I would put both in and use both(if you can)or only use the one that your manufacture recommeds for the fuel your burning at the time. I hope some of this helps these are just my experinces, and remember check with your manufacture for proper operation.
Have a great day, Eric

Coalfire wrote:Out door temps were in the high 50's I checked my draft before the baro (with the mpd open and closed made a negligable differance) and it was -.06, Now I checked it before the the MPD and it was still -.06. This was interersting.

Where MPD players need to be careful is with a forced draft appliance. Your stack #s may look real nice, but in some cases, they and particularly the firebox may go to positive pressure draft when the blower is running.

I have been tending fires for 20 years. I have always seen used and used my self Manual Pipe Dampers. My grand parents on their air tight stove even had a manual pipe damper. At my house I have used a manual pipe damper on wood stoves and furnaces. I also have a manual pipe damper on my coal stove. I have actually noticed less ash buildup in my chimneys over the years compared to friends that have baro or no damper. I burn less fuel as well. Baros are ok in some circumstances but i would never use one unless I had a manual pipe damper in line.
Randy

I ran a Buderus hand fed for 27 years with no damper whatsoever. The bimetalic draft control on the stove managed everything. I now have a Keystoker 90 top vent stoker with a barometric damper dialed in as advised. Both stoves performed very well. The Keystoker is far less work with a wider burn time due to it's controls and the Coal-trol.

I, also am in favor of using a Manual Pipe Damper on a Handfired Coal Stove. I used one for 29 years with the Warm Morning stove and presently using one with the Buck Model 24 Coal Stove. In my opinion, when you get use to the Manual Pipe Damper it seems you can fine tune the burn of your stove a little bit better. Also, I get more heat out of the stove and less wasted heat out the chimney. I can really notice the difference with the MPD.

I agree w/buck24--I use a MPD on my hand fired Hitzer--after reading many posts I called Hitzer & spoke w/ a couple shop guys who use nothing damper wise I decided to stick w/ what I have experience with--I kept my MPD about 2/3 closed all winter & on shut down & clean up last week,noticed that there was very little fly ash above the damper--if it ain't broke,don't fix it--I keep saying--a stove is like a good woman,find out what she likes & stick with it

This is the most confusing subject on this board..lol

grumpy wrote:This is the most confusing subject on this board..lol

You're right, the Chubby comes with a MPD built right into the flue breach and the Harman manual strongly recommends not using one. I guess it comes down to "what ever works".

I am planing to burn coal this year in my old Florance, I am just worried about an over fire if the winds pick up and I'm not paying attention. I also burn wood so a baro is not wanted. I could put one in and cap it for wood I suppose but the thing is 50 people will tell me I should have a Baro and 50 people will tell I do not need one....

Well, since you're burning wood too, I would forget about the baro and install the MPD. I have both on my Chubby and with the MPD closed about 2/3 the baro only moves when it's windy out. I suppose 50 people will agree and 50 people won't. What ever floats your boat.

LOL.... Thing is I don't think there were Baro's when my stove was bulit,, 1914 ...

Bottom line... you burn wood in your stove so, no baro. MPD for control.

Yeah I think so, looking forward to it too..