I am replacing an old stove with a new EPA one which requires 6". Due to clearance issues I am installing double wall 6". The existing stove pipe is single wall 8". I was hoping to install a 6" to 8" adapter right below the ceiling support box to eliminate messing with the support box. Does such an adapter exist? Also, the overall height of the chimney is about 12' and the stove (Englander 17-VL) recommends 15' of 6". I was planning on just increasing the class A chimney with additional 8" if there was a draft issue. Do you think that will work or what would you recommend?
Double wall 6" to single wall 8"
- Thread starter rwieder13
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In the PNW's mild climate you will want to have the chimney as correct as possible for burning when temps are in the 40's. It's ok to go up to 8" chimney but sub-optimal for draft. This is going to be compounded by the short chimney. Is 12" from the stove top to the chimney cap or is that just the chimney pipe with additional footage in the connector pipe?
The 12' is from the stove top to the chimney cap. It is about 5.5' from the stove top to the ceiling, about 3' in the attic, and then 3' from the roof to the chimney cap.
We hear this both ways. The 8" stove guys say you need 8" pipe or you won't get enough draft, the 6" stove guys say you need 6" pipe or you will not get enough draft. Seems to me that the 8" will suck harder than 6".
The larger chimney size in proportion to the flue requirement will cool down flue gases quicker, spoiling draft. It doesn't matter if it's 6" increasing to 8" or 8" increasing to 10", at some point the draw is harder. There is more air to displace. Imagine trying to drink out of a bucket with a 1" pipe vs a 1/4" pipe. It will take more suction to pull water up the 1" pipe because there is more weight of water. The chimney should be matched to the stove size. Often once the chimney gets over 2x the flue requirement draft will fail.
If the stove is very large and providing a lot more fuel for the engine of draft then there can be enough heat to displace more air and pull more air into the larger firebox. In that case an 8" flue may be required.
If the stove is very large and providing a lot more fuel for the engine of draft then there can be enough heat to displace more air and pull more air into the larger firebox. In that case an 8" flue may be required.
nope not on a 6" stove. There is to much volume and therefore allot of velocity will be lost. This along with the expansion of the gasses will allow for allot more cooling which will lessen draft even more.
Your draft may not be good enough with the 8" chimney. There are 6 to8 adapters available for the Duravent system, I would assume there are for others. I have mine installed just where you are wanting to. My draft is not perfect, but functional, but I do have more chimney than you, it would really pull draft with an 8" flued stove, but with the 6" stove, it is not as strong. Somewhere about 18' from top of stove to chimney cap.
What is the brand of your chimney?
What is the brand of your chimney?
I figured it wouldn't draft as well and expected to increase the height of the chimney, I just don't know how far that will be until I have everything hooked up inside. I completely agree and will accept my draft not being perfect as long as it is functional. My chimney is Duravent as well.
You initially say 6 inch double wall to 8 inch single wall. Did you mean 8 inch class A? If you need 6 inch double wall for clearance issues how can you change it to single wall at the chimney connector?
6" single wall plus 18" clearance is 21" from centerline to wall. 8" single wall plus 18" clearance is 22" from centerline to wall. 6" double wall plus 6" clearance is 9" from centerline to wall.
I understand the clearances that's why I asked. The OP has to use double wall to meet clearance requirements but wants to convert double to single at the chimney connection. I would think that negates using the double wall in the first place?
Since the adapter will be right at the ceiling I figured the clearances wouldn't be an issue. I understand there will be a couple inches which doesn't technically meet clearance but didn't think that was a big deal considering the existing single wall 8" isn't even close to meeting clearance.
Heftiger
Feeling the Heat
I wonder if it will be aesthetically pleasing. Going from double wall 6 pipe to single wall 6 adapter is going to look funny, don't you think?
Let it look funny. You want to keep the flue gases as hot as possible in this case to compensate for the heat loss as they expand in the 8" pipe.
I agree with begreen, I completely understand it won't look ideal, I am just trying to keep the 6" as long as possible. So do you think an adapter like this will work in this instance?
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The crimped 6" would go inside the Duravent DVL and then screw on the outside of the existing 8". I believe the 8" part of the adapter will even fit inside the ceiling box to ensure clearances are still met.
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The crimped 6" would go inside the Duravent DVL and then screw on the outside of the existing 8". I believe the 8" part of the adapter will even fit inside the ceiling box to ensure clearances are still met.
Given the direction of flow (upward, 6" into 8"), I wonder if the crimping of that adapter is on the wrong end. If the crimped 6" end of the adapter fits between the inner and outer walls of the 6" double pipe, that's ok. But if I were designing it, I'd have the 8" end of the adapter fit inside the bottom of the 8" chimney. If the adapter to chimney fit is tight, it probably would work ok. Other thoughts on this?
Some years ago I set up a small stove with a top 6" outlet to feed into an existing 7" insulated chimney. I used an adjustable double wall 6" section to go from stove to ceiling, so I could position the stove closer to the wall per allowed clearances. I bought a single-wall 6-7 adapter to connect to the chimney. To address the clearance issue in the vicinity of that single-wall adapter, I hung a foot long piece of 1" black wall pipe from the bottom of the chimney as a radiation shield.
Heftiger
Feeling the Heat
My understanding was the crimped end always went down to prevent creosote from running down and out of the pipe. Maybe I am mistaken on this though.
rwieder13, if you have duravent, go to their website or go to a knowledgeable local dealer and get the proper pieces. I believe you are trying to do what I have done on my system. I have an older Duravent 8" triple wall chimney, with a support box in the ceiling of the basement, and have it attached to 6" double wall dvl pipe. The parts I used I believe are the 8dvl-adc chimney adapter ring with trim, and the 6dvl-x8 increaser. Make sure you are getting the right pieces for your system. Duravent has their catalog on their web site, you will need to look at the DVL part of the catalog to see the different pieces available. Then you will need the proper length of dvl pipe that will slip, and a dvl 6" stove adapter. The support box will not be moved, nor the chimney above it, but that old chimney adapter ring was tough to get removed. The new one just slips up there, and is held in place with the screws of the trim ring into the support box itself if I remember correctly.
When done with the proper pieces, you will have a nice chimney system. No need to use any single wall pipe in it at all, and would not recommend it. If you do not have a good local dealer, then once you figure out what parts you need, google them for the best prices. I believe some of the Hearth.com sponsors will have very competitive pricing. Hope this helps.
When done with the proper pieces, you will have a nice chimney system. No need to use any single wall pipe in it at all, and would not recommend it. If you do not have a good local dealer, then once you figure out what parts you need, google them for the best prices. I believe some of the Hearth.com sponsors will have very competitive pricing. Hope this helps.
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