Anybody had to put a damper on the flue to limit the amount of heat lost up the chimney due to overdrafting? I have a PE Summit and feedback that I have received indicate that I may be overdrafting and therefore not producing as much heat as the stove was designed for. I have about 30' of vertical including stove pipe and chimney and approximately 3' of horizontal. Infput on creosote buildup, success stories or other input is appreciated regarding damper installation.
Damper on Flue
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Do you have a probe thermometer on the flue? That will tell you a lot about how the system is performing. I have had a damper on a couple stoves. No increase in creosote as long as good burning practices are maintained. It does make the stove more responsive to air primary air control. With a 30ft stack I would consider adding one, especially if the stove is hard to regulate. If the stove is still responsive to the air control, that is it dampers down properly, then it may not be necessary, especially if the stack temps are normal.
BeGreen said:
I do have a probe thermometer. I guess if I add the damper under the probe thermometer it should be fine as long as I monitor it. How far above the damper would you recommend the probe to be? In general have you found that you leave it 3/4 open or in one position once you find a sweet spot or do you open it up all the way when you light your fire and the damper it down after it is going, just curious. The one air control is nice that I have now so if we don't have to mess with the damper and the priomary air everytime we add wood that would be great.
webbie
Seasoned Moderator
A barometric draft regulator can be a good idea - the up side is that is automatically spoils the draft as the weather and chimney change, the down side (which is not really one in terms of most new stoves) is that it will let room air feed a chimney fire if you have one. Again, should not be a problem with newer stoves, but it would be good to keep a piece of broil foil or some other "quick cap" for the baro around.
Craig, doesn't that have the effect of cooling the flue gases? A manual damper does slow down the flue gases, doesn't cool them with room air. I would be concerned about creosote build up with a baro.
Danielson, what probe temps are you normally seeing? How well does the stove regulate now?
As to using the damper, it depends. For example, we're burning up some hemlock now. The thick splits burn slowly compared to our maple so we leave the damper open and just regulate with the air control. When burning the maple we leave the damper open when starting up and trhough the first burn. Then we throttle it about 3/4 closed when the stove and stack are good and hot. We always open it before opening the stove door to avoid smoke spillage.
Danielson, what probe temps are you normally seeing? How well does the stove regulate now?
As to using the damper, it depends. For example, we're burning up some hemlock now. The thick splits burn slowly compared to our maple so we leave the damper open and just regulate with the air control. When burning the maple we leave the damper open when starting up and trhough the first burn. Then we throttle it about 3/4 closed when the stove and stack are good and hot. We always open it before opening the stove door to avoid smoke spillage.
danielson said:
You will be opening that damper all the way before you open the stove door. At least you will be after you forget to a couple of times and get a face full of smoke.
Probe temps range depending on the air inlet control of course. When I load the stove up I open the primary all the way up and let the probe get to 800 then I cut the primary back to about 1/8 to 1/4 setting. The probe climes to about 900-1000 and runs there for a while then slowly decrease as the fire dies down. I burn red and white oak and am getting good burn times. 8.5 hours at primary down to about an 1/8 open. I have a stove top thermometer too but with the blower on I don't know how accurate it is. With the blower off the stove top can get to 700 pretty easily, with the blower on it doesn't get much above 500. Any insite is appreciated. I think the damper may be worth a try, but I am hesitant to install it for fear of creasote buildup and potential chimney fire. I think it may be worth a try. I would just assume get more heat in the room and less up the chimney as long as the chimney stay warm enough to prevent creasote buildup.
That's hot. At those temps creosote should not be building at all. I think the damper is in order. Even with the damper I am guessing you will be seeing 6-700 degree stack temps, still a very safe range for creosote buildup.
BrotherBart said:
I would hope I wouldn't get a face full of smoke. I believe my intention is to make the stove draft like it was designed to from the factory. So my goal, I think, would be to damper it down until you get the draft to where it was meant to be for the stove to run at it's optimum efficiency coming from the factory. This setting should not create the backpuffing situation unless I am missing something.
Any suggestions or insite is appreciated.
BeGreen said:
Thanks for the input, I am going to give it a try. I will post my results after I run it a couple of day. Appreciate all of the help.
pistonslap
Burning Hunk
I have a manual damper installed in my flue and it works well. It extends my burn times as well as gives me more control over my chimney temps. I start my fire with it open and leave it open until I get a good bed of coals going, then I can usually turn the damper almost completely closed. After that I can control my chimney temp with my primary air. Being an old non-cat that's all there is to it. And yes, I do believe it saves a lot of heat from going up the chimney.
webbie
Seasoned Moderator
BeGreen said:
Again, a mixed bag.
A baro keeps the air moving up the chimney faster - air and exhaust - much faster! Better stock flow creates less residence time, therefore less creosote. Again, not suggest as much (or at all) for pre-EPA stoves. I may have mentioned before, but this was suggested to me by one of the lead researchers at Corning, when the cat converter for stoves was being developed.
I think some tests were done with both cats and non-cats - with good results (higher efficiency, less creosote).
BrotherBart said:
Absolutely guaranteed to happen. Usually in direct connection with the amount of beer, wine, scotch (fill in your pleasure) imbibed before said door opening.
I have and old Earth Stove and I don't have a Baffle or Cat or anything. I installed a Damper right at the top of the stove the goes into a 90 then straight back throught the wall to my SS liner. My burn times are lasting longer and have better beds off hot coals. I have to thermostates and one on top of the stove and one on the vertical piece of the stove pipe. The reading on top the stove is usually about 500 or 450 and the one on the pipe is usually 250. Thats with the damper completly closed and air control on low. All i have to do is open the Pipe damper and add wood and close damper and done, never touch the air intake. I works really nice. I don't really worry about cresote. Every other night i get it really really hot and leave the damper open and get it burnt out.
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