Installing a damper in my flue

Discussion in 'Modern EPA Stoves and Fireplaces' started by Paul Dokken, Jan 18, 2021.

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  1. NVhunter

    NVhunter

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    SD Steve , what type of insulation do you have around the chimney thimble there? I have cinder block wall around mine in a daylight basement and want to insulate the wall but am throwing different ideas around. I want to move the stove out a few inches and cover the insulation with durock and put up veneer stone to make it look better over the durock and insulation... just curious what you have there.
     
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  2. yooperdave

    yooperdave

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    Appears to be reflective bubble wrap typically used in HVAC (go figure).

    When staple up radiant heat is added to subfloor between floor joists, this bubble wrap is stapled to the sides of the floor joist to hep reflect the heat upwards and through the floor.

    [​IMG][​IMG][​IMG]

    Or it can be repurposed such as steve has. Looks like he used the overkill method of attaching it (with fender washers and zip screws) to help create a reflective heat barrier near his venting.
     
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  3. SD Steve

    SD Steve

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    As Yooperdave pointed out, yep, thats what I did. The original concrete foundation of the house had crumbled on that side of the house. It was repaired with a wooden, insulated wall with plastic on the opposite side for moisture. When I put the wood stove in, I put up the reflective bubble wrap to reflect more heat into the basement. Simple as that.....
     
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  4. yooperdave

    yooperdave

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    I have an OWB here and actually shut of the gas for the winter....once it is lit. Only two things here using NG are the furnace and the water heater.

    That being said, I did grab some cutoffs from previous jobs and wrapped the outside of the water heater with that same reflective bubble wrap! :D
     
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  5. MAF143

    MAF143

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    Sorry, late to the thread... I have a flue damper in my installation and use it only when putting in a full load of wood in the stove. I have 33' of chimney and it pulls a very strong draft. After getting the stove up to temperature (with the secondary tubes kicked in) I can close down the dampers on the stove itself completely and it still burns too hot because of the hight amount of draft that the chimney pulls. I can close the chimney damper almost all the way down (2 o'clock position when 3 o'clock would be completely closed) and it puts the stove into a long, hot burn. When I was first using this stove and following the instructions, it reccomended that no damper be put in, but running without using the damper let the stove get too hot and it would burn up a full load of wood in in just a few hours. Due to the high draft condition I have the flue damper above the stove has to be used along with the stoves controls to get optimum burn.

    I drill holes on both sides of the pipe, but the second hole I use a smaller bit so it is tight. I also draw a line around the pipe to ensure I get it level and also measure around the pipe and place the second hole so it is directly opposite of the first hole. I too like it at least 3 feet above the stove so that the handle gets less hot, but I still always have a glove on when touching it. I don't think placement makes a difference as far as holding the heat down in the stove. The air moving through the pipe is a serial circuit and closing the damper slows the flow so the hot gases in the flue pipe can transfer their heat out through the pipe. The slower the gas flows, the more heat is transferred to the room before exiting throught the wall to the chimney. Also the slower it's moving the less heat is being generated inside the stove in the first place.

    I'm a fan of having a damper in the flue for many reasons, including just in case of a chimney fire (low chance here).
     
  6. JOTULMAN

    JOTULMAN

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    Duravent told me they want the damper just above the stove but in this location you will need to wear gloves to adjust. This was the best spot for me because I slanted 45 degrees after the damper. If you get a draft gauge you can actually dial it in. Always open before reload and be aware some get smoke during reloads just because the damper by itself is a restriction. I think they are great to control flue temps and overdraft. My stove burned at .12 and i put the damper 1/3 or less and it moves the draft to .08 .09 which Jotul recommends. This is my first year so I cant tell you the long term chimney / creosote impact. I like the one piece duravent but had to use a block of wood to tap it in so its level. I put a hole on the lower back side for the Dwyer Magnahelic draft meter. Im still learning...
     
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  7. fishingpol

    fishingpol

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    About how tall of a flue do you have?
     
  8. JOTULMAN

    JOTULMAN

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    Outside the SS Duravent goes up 15 feet, and thinking of raising it. 3 - 48" sections and the last top section looks like 36" inches. I live next to a highway and im on the back side of the house.
     
  9. fishingpol

    fishingpol

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    So does the draft meter pick up changes with a dryer running, bath vent or a range hood fan? Just curious.
     
  10. JOTULMAN

    JOTULMAN

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    Open the outside door about 5 feet away moves the shakes the needle slightly. I haven't done the dryer boiler bath/kitchen vent, door closed test yet...(but I have seen the videos) But im not sure if that impacts draft or just neg pressure...dont really understand the difference yet ...I dont have the optimal setup. I have two adjustable 90 with 48 inches of pipe between them and the thimble.

    But one day after an overnight burn...I had coals in the ashpan and the stove area and the temp dropped outside around 5pm quickly (causing a very cold flue) and my ultra low co meter read 12 ppm for a short period. I dont what happened but it could have been the steam boiler and upstairs kitchen etc. Its never happened again but I now have a 4 inch passive air vent open. I didnt have the draft gauge at the time.

    If I look at the draft gauge when the stove is off I can tell how easily the stove will light at startup. A zero will tell me if need to heat the flue up or ill get smoke spillage. A .04 an I get an easy light.
     
    Last edited: Feb 23, 2021
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  11. Flamestead

    Flamestead

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    When I started researching modern wood stoves, around 2010, the prevailing opinion was the stovepipe damper was a thing of the past. Today I think it is much more widely accepted as a useful control.

    Woodstock told me a “typical” draft was in the 0.03” to 0.07” range (inches of water column). Mine measured at 0.12” on a typical day, and as high as 0.21” in much colder, windier conditions. We added a damper and use it.
     
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  12. Highbeam

    Highbeam

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    Since then, the regulations have gotten very tight and many manufacturers accomplished compliance by doing things that now make it a good idea to have a pipe damper.
     
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