How To Increase Chimney Draft

Re: How To Increase Chimney Draft

PostBy: KingCoal On: Tue Dec 17, 2013 3:35 pm

ok, then 90's can't be worth 10 ft. either or my chimney would be -7 ft. functionally.

i have also considered coming out of the stove collar with a "T" laying flat, going into a 90 on each end, with a bit of pipe, then 2 more 90's coming back to a "T" and into the wall thimble.

i've seen this construction on european stoves that were actually cast as part of the stove body.

might be an extra heat radiator too.
KingCoal
 
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Re: How To Increase Chimney Draft

PostBy: BPatrick On: Tue Dec 17, 2013 6:22 pm

What would be more effective, insulating the pipe, increasing the height of the pipe above the roofline, or removing any right angle bends except one right out of the stove and up out of the roof?
BPatrick
 
Baseburners & Antiques: 2 Crawford 40 Baseheaters
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Re: How To Increase Chimney Draft

PostBy: BPatrick On: Tue Dec 17, 2013 6:22 pm

Forgot to post this on last post: I have a feeling that a combination of all 3 would really make the most difference.
BPatrick
 
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Re: How To Increase Chimney Draft

PostBy: lsayre On: Tue Dec 17, 2013 6:31 pm

Franco B brings up an interesting point here that Lightning has introduced and is addressing in another thread. Contrary to intuition, a short chimney could work well provided that the stove is upstairs where the home is naturally at its highest pressure levels. And a medium height chimney could work well if the stove is at the midrange height of the home, where one would presume to find the homes neutral pressure plane. It boggles the mind.
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Re: How To Increase Chimney Draft

PostBy: blrman07 On: Wed Dec 18, 2013 7:58 am

NOOOOOOO....not the neutral pressure range thing again????????

:jawdrop:
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Re: How To Increase Chimney Draft

PostBy: Lightning On: Wed Dec 18, 2013 9:18 am

blrman07 wrote:NOOOOOOO....not the neutral pressure range thing again????????

:jawdrop:


Yes sir, its all about stack effect in the house and location of the neutral pressure plane :lol:
Lightning
 
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Re: How To Increase Chimney Draft

PostBy: BPatrick On: Wed Dec 18, 2013 10:07 am

"It's all ball bearings now" (Fletch quote) couldn't resist. Great information.
BPatrick
 
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Re: How To Increase Chimney Draft

PostBy: MudFlapLip On: Thu Dec 19, 2013 3:46 pm

Some may say this method is not recommended but it works for me an I haven't had an issue since. I had a draft problem last winter during a period of warmer outdoor temps. I was getting a wicked exhaust smell from the stove door. It filled my entire basement but the CO alarms never went off. I called the chimney contractor who built my chimney and he said take a piece of loose insulation (without the paper of course) and tightly stuff it just inside the cleanout door. He said don't go all the way to the back, just inside the door then close it. Walla problem solved. Apparently the door leaks a small amount of air and will interfere with the chimney draft especially on low draft conditions. I called a chimney sweep company who recommended the same exact thing. Again this method may not be recommended by others and not always work. It worked for me.
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Re: How To Increase Chimney Draft

PostBy: BPatrick On: Thu Dec 19, 2013 3:57 pm

piece of loose insulation (without the paper of course) and tightly stuff it just inside the cleanout door. He said don't go all the way to the back, just inside the door then close it. Walla problem solved. Apparently the door leaks a small amount of air and will interfere with the chimney draft especially on low draft conditions.

I don't understand, what are you referring to as clean out door. I have a Crawford 40 base heater. I don't know where I would be able to put that?
BPatrick
 
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Re: How To Increase Chimney Draft

PostBy: MudFlapLip On: Thu Dec 19, 2013 4:08 pm

The cleanout door (assuming you had one) would be near the base of your chimney either on the inside of the house or outside. My cleanout door is inside the house behind the stove. It should be a black cast iron door. In the event someone were to burn wood you could sweep the chimney and then remove the creosote and other debris from the cleanout location. This is also a location from where you could use a mirror to see up the chimney for blockages or debris.
MudFlapLip
 
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Re: How To Increase Chimney Draft

PostBy: Sunny Boy On: Thu Dec 19, 2013 4:10 pm

BPatrick wrote:piece of loose insulation (without the paper of course) and tightly stuff it just inside the cleanout door. He said don't go all the way to the back, just inside the door then close it. Walla problem solved. Apparently the door leaks a small amount of air and will interfere with the chimney draft especially on low draft conditions.

I don't understand, what are you referring to as clean out door. I have a Crawford 40 base heater. I don't know where I would be able to put that?


He's talking about the one in the chimney, not the stove.

Most masonry chimneys are built with a cast iron door and frame near the base to allow cleaning out anything that can fall down the chimney, such as ash, wind-blown leaves, critters, etc..

The doors don't seal well, and as he said, they can cause cool air leaks into the chimney cooling off the flue gases and slowing draft.

Paul
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Re: How To Increase Chimney Draft

PostBy: Cyber36 On: Fri Dec 20, 2013 2:14 pm

Rob R. wrote:Generally speaking, I think most chimney caps either do nothing to improve draft or slightly reduce it. If you want to increase the draft, you either need to raise the height of the chimney or increase the temperature of the gasses going up through it.

This ^^^^^^^^^^^^^^^^^^
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Re: How To Increase Chimney Draft

PostBy: Sunny Boy On: Fri Dec 20, 2013 2:35 pm

Cyber36 wrote:
Rob R. wrote:Generally speaking, I think most chimney caps either do nothing to improve draft or slightly reduce it. If you want to increase the draft, you either need to raise the height of the chimney or increase the temperature of the gasses going up through it.

This ^^^^^^^^^^^^^^^^^^


I can agree with that is it's not the venturi type.

Especially if wind gust pressure is reducing the available cap opening area. I get that with my fireplace because the slate cap on top only leaves enough square area of all four side openings totaled up to equal the chimney flue square area without wind. Wind gusts affectively close off some of that opening total area and my fireplace puffs back. Only way to prevent it is to keep a roaring fire going all the time to get/keep a really strong draft when it's windy out. Or keep the fireplace glass doors shut all the time.

Paul
Sunny Boy
 
Hand Fed Coal Boiler: Anthracite Industrial, domestic hot water heater
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Re: How To Increase Chimney Draft

PostBy: dustyashpan On: Sat Dec 21, 2013 6:18 pm

BPatrick wrote:What would be more effective, insulating the pipe, increasing the height of the pipe above the roofline, or removing any right angle bends except one right out of the stove and up out of the roof?


imho, chimney height #1 thats where it gets draw. insulated #2 keeps heat makes any chimney pull harder. #3 bends in chimney design parameter keep minimal. if its got the first 2 traits big time, can overcome #3 bends. like this picture below. strong draft can pull smoke straight down through 3x 90's. factors 1,2 give horsepower to draw. factor 3 detriment to minimize. I went insulated SS, one 90 bend, never looked back. draft improved, stove burned better, more heat. prior coal gas ate single wall black stovepipe like candy. definite double wall ss chimney & ss cap outside on roof. masonry most durable, downside absorbs & loses heat. insulated SS good compromise. your a bb guy understand why you want max draft. good idea, those need strong draft to pull bb mode passages effectively.
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