Chimney draft

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Anika1

New Member
Jun 30, 2015
7
Springdale, PA
I am looking to buy an older Cawley Lemay, Lange or Jotul 118. I have a chimney which is about 19 foot high. The chimney comes straight up and angles over 2 flue liners at about a 30 degree angle and then goes straight up from there. Also the chimney has 11 1/2" x 7 1/2" flue liners. I think this would have a good enough draft but I'm not sure. In my other homes that I owned, I used to have to put a piece of paper up the stove pipe and light it to reverse the draft. In a Lange 63O2K, you are unable to get to the pipe. I guess in this particular stove, you would have to put 3 or 4 pieces of paper in the stove to reverse the draft. Does anyone have experience with this type of stove or have they had problems reversing the draft in the chimney when they start the stove in cold weather.
 
Welcome to the Forum;
You should have the flue the same size as stove outlet all the way up. The larger the flue, the more area you're trying to heat to get it to rise and make the stove work. (the lighter rising gasses allow atmospheric air pressure to push oxygen into the low pressure area in the stove) The less you have to put up the chimney, the more efficient the stove, so you will notice much more heat out of the stove with the correct size chimney. Square inch area of a 6 inch pipe is 28.26 square inches. Your liner being 11.5 X 7.5 = 86.25 square inches. So that's 3 times the heat you need to leave up to prevent creosote at the condensing point. (250* f. all the way up)
It takes much more heat to make your larger flue start drafting and there are many other factors that contribute to cold air dropping down or reversing.
A larger flue is capable of a larger stove or fireplace, but that doesn't make it a stronger draft. An insulated liner that stays hot inside and has much less area to heat inside requires little to nothing to get it drafting.
 
I can tell you that a 7 by 11 flue is way to large for a cawley many are only 5" outlets. some are 6". I would recommend an insulated liner for sure.
 
Welcome to the Forum;
You should have the flue the same size as stove outlet all the way up. The larger the flue, the more area you're trying to heat to get it to rise and make the stove work. (the lighter rising gasses allow atmospheric air pressure to push oxygen into the low pressure area in the stove) The less you have to put up the chimney, the more efficient the stove, so you will notice much more heat out of the stove with the correct size chimney. Square inch area of a 6 inch pipe is 28.26 square inches. Your liner being 11.5 X 7.5 = 86.25 square inches. So that's 3 times the heat you need to leave up to prevent creosote at the condensing point. (250* f. all the way up)
It takes much more heat to make your larger flue start drafting and there are many other factors that contribute to cold air dropping down or reversing.
A larger flue is capable of a larger stove or fireplace, but that doesn't make it a stronger draft. An insulated liner that stays hot inside and has much less area to heat inside requires little to nothing to get it drafting.

What stove would you recommend? Would a Defiant or Valiant work since they have 8 inch pipes?
 
8 inch round is 50.24 square inches. Still needs a liner to correct the size.
Most all newer stoves require 6 inch, so if you're going to make it right, do it for any newer stove as well. In time codes and requirements are likely going to require a newer stove and you will need a 6 inch anyway. The chimney is more important than the stove. Any of those stoves will work good with the correct flue, NO stove will work correctly and efficiently with the wrong flue.
 
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