Masonary Chimney Question?

Masonary Chimney Question?

PostBy: woody30 On: Fri Aug 17, 2007 9:09 am

OK, I'm going to build a masonary outside chimney, and it won't be very high as this is for a ranch. And the chimney will be near the eve (front) of the house. So what size should the chimney be, I'm thinking 8x8 but some say make it the same size as you stove. I'm going to be buying a Stoker 90 or a Hitzer 354 . I think they are both 6" . I'm thinking the chimney will only be around 14' or so from the ground up. Any thoughts would be appreciated.
woody30
 

PostBy: coaledsweat On: Fri Aug 17, 2007 9:47 am

I would think 8X8" is fine. I think you should be at least 18' and prefferably 20' high above the thimble. Not much chance of the house competing with the chimney in a ranch.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: woody30 On: Fri Aug 17, 2007 10:26 am

Thanks for the reply Coaledsweat I appreciate it. I'm not sure that it will be that high from the thimble , because this will be only a couple feet from the front of the house. But I will let my mason friend deal with that. Now is there any rule of thumb where I should put the thimble in relation to the stove? I think the Stocker 90 is 39", and I will be putting something like brick under it. So would 48" from the floor be about right? Thanks again.
woody30
 

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PostBy: coaledsweat On: Fri Aug 17, 2007 10:35 am

It isn't critical, just make sure any horizontal pipe & the thimble are inclined upward slightly on its way to the chimney. Try to set it up with as little horizontal run as possible (the ash tends to fall out and accumulate). Nothing should protrud into the chimney, pipe or thimble.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: woody30 On: Fri Aug 17, 2007 2:16 pm

Thanks good tip on the slight incline.
woody30
 

PostBy: jpen1 On: Sat Aug 18, 2007 12:46 pm

That chimney is pretty short to run a hand fired appliance . Is there any other homes that are higher close by where you are putting your chimney? If there are I would be concerned about the hitzer or any other hand fed stove being able draft well enough to maintain a good coal fire. I have a hand fired wood/coal combo stove in my cabin with a similar chimney height and have problem maintaining draft in less than ideal conditions like when it warms up in the daytime. I have a stoker at home and have draft any time even with a very small fire however my chimney is about 28'-30' above the thimble.
jpen1
 
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: 110 Boiler

PostBy: coaledsweat On: Sat Aug 18, 2007 12:54 pm

I just reread this thread and yes, because the chimney is exterior I would add another 4-6'. It should be 24' at the very minimum from the thimble and prefferably higher.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: jpen1 On: Sat Aug 18, 2007 4:19 pm

I guess I should clarify A little better . I think if you go with the stoker you will have enough draft to run it provided your new chimney will receive un osbstructed airflow. Also if you insulate around the chimney with vermiculite or something similar you can help the chimney draft better. Also with a stoker you can add a draft inducer to help if you should have problems with it drafting. Also I see you are putting the chimney near the eve orlow point of your roof line. There is a formula and I believe for every eight linear feet away from the peak you can only drop 2' below the roof's ridge. However I think you want it a little higher than you roof's ridge line to get the best draft especially if you go with a hand fired appliance.
jpen1
 
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: 110 Boiler

PostBy: woody30 On: Sat Aug 18, 2007 6:32 pm

OK, I just measured my peak to ground and its under 18'. Now if I went with a chimney 24' up from the thinble like you say Coaledsweat, that would give me a chimney around 30'. I have never seen a chimney that high on a ranch any where in upstate N.Y. at least. From what I understand you have to be 2' higher than the roof 10' away, so that would give me a chimney of around 16' to 18' . Do I understand this right or am I not seeing something here that I should? Keep the info coming as I'm learning as I go here. Also I have another post but will ask it here also as it has to do with Stockers. Does anyone have a Keystocker 90 on their main floor, and if so does the fan that blows the heat out from under the top make too much noise or isn't it not too bad? Thanks
woody30
 

PostBy: coaledsweat On: Sat Aug 18, 2007 7:54 pm

How many are running a coal fired heating appliance though? You don't need a lot of chimney for oil or gas as they are forced draft. The 2' at 10' is to keep the smoke away from the home, not for draft.
If you have a stoker it doesn't need quite as much draft as a hand fired. The absolute minimum for a hand fired is generally accepted as 20' from the appliance exhaust port. Because your chimney is going to be exposed to the cold I would reccomend the additional height. You could reduce it by insulating the flue as mentioned earlier in this thread, if I had the steam I would do both. As I said earlier, in a ranch you won't see the house competing with the chimney as bad as a two story will. But with any combustion byproducts it is best to err on the side of caution. The worst thing that could happen if the chimney is too tall is that your appliance will perform better, and that really isn't a problem. If you unit is on the first floor and is 4' to the exhaust from the floor and your first floor is 2' off the ground, your chimney is going to need to be about 8' higher than the peak. Cheating on your draft will give you poor performance no matter what the appliance is. And poor performance is not going to make you happy with the project. We are all about happy here. :)
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: woody30 On: Sat Aug 18, 2007 8:34 pm

Wow, This has been a real eye opener that's for sure. What is the best way to insulate the chimney? I'm going to use block bond to give the chimney more strength, would block bond help to insulate also ? Or can you buy an insulated chimney block? Thanks
woody30
 

PostBy: Yanche On: Sat Aug 18, 2007 8:48 pm

A tall chimney will provide the best design. If it doesn't fit the looks you want, build it the height the looks best and use a draft inducer. Field Controls makes draft inducers that are approved for use with coal appliances. See: http://www.fieldcontrols.com/draftinducers.php
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

PostBy: coaledsweat On: Sat Aug 18, 2007 9:06 pm

If you lose power often or for extended periods do not go with the draft inducer.

I'm no expert on chimney construction, but this ought to keep you busy.

http://www.google.com/search?hl=en&q=ch ... nstruction

Check the one marked evil. :twisted:

http://www.google.com/search?hl=en&q=chimney+insulation
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: woody30 On: Sat Aug 18, 2007 9:29 pm

Thanks to both of you I appreciate the info, I will have to find more info on insulating the chimney.
woody30
 

PostBy: Yanche On: Sat Aug 18, 2007 9:40 pm

coaledsweat wrote:I'm no expert on chimney construction, but this ought to keep you busy.
I think we need a coal chimney expert. Take a look at this link:

http://www.repp.org/discussiongroups/re ... 7-2003.xls

It's a calculation for the combustion of wood in a cooking stove. Note how the author has carefully calculated the moles of gases produced by burning the wood, added excess air and then determined chimney draft. Anyone want to port the calculation to Anthracite coal? Formula C240 H90 O4 NS. I know get a life. :)
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

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