connector stove pipe length for through the wall setup

[Rob_Red]

Hey all,

I am putting together a through the wall setup and am now wondering is there an Ideal length to keep the connector pipe? Can it be too short?

I will be running double wall stove pipe vertically for about 28 - inches then will have a 90 that goes into an 18" section insultated chimney pipe through the 12" wall and hits another 90 (T section) that goes straight up through the soffit.

 

[gthomas785]

If you are referring to the pipe going from the stove to the chimney, then no it cannot be too short. Just get from A to B. You want to avoid sharp bends and horizontal runs as much as possible so I'd put a 45 degree elbow right at the wall and another 45 down to the stove if you have room to do that.

If you are talking about the horizontal piece of chimney pipe coming through the wall, it needs to either stick out far enough to get you past the clearance of the connector pipe or terminate into a listed wall thimble for that purpose

 

[Rob_Red]

Talking about paragraph 1 - Stove to chimney.

I assume the use of 45s over a single 90 is to prevent creosote from building up?

Thanks for the info.

 

[begreen]

Talking about paragraph 1 - Stove to chimney.

I assume the use of 45s over a single 90 is to prevent creosote from building up?

Thanks for the info.

The through the wall Class A connector pipe should be kept as short as possible while covering clearance requirements and mfg guidelines for the amount that needs to project into the room from the thimble.

On the stovepipe, using 45s to soften the 90º helps draft by lowering resistance in the pipe. Sometimes this is necessary if the draft is weak due to a short chimney or negative pressure in the room like in some basement installs. How tall will the chimney be?

 

[Rob_Red]

How tall will the chimney be?

The chimney will be 25ft off the T and the T will be 6 feet of the ground, the stove pipe will be about 30 inches or so. The class A is taking the place of a masonry chimney made of concrete chimney ring with clay liner, that was similar in specs, and was torn down.

The old setup used to draft very well and had a stove pipe using a 90. I was planning to replicate because I don't love the look of the 45's.

Also this setup is in my living room and I don't have negative pressure problems

 

[Shrewboy]

Post some pictures if possible :D

 

[gthomas785]

I was planning to replicate because I don't love the look of the 45's.

I agree a 90 looks better. With 25 feet chimney you probably have enough height it would work fine.

I have one 22' chimney with a 90 and another 15' chimney with a 45 to a 90 (chimney is off center). They both burn fine but the shorter one is marginal and I often get smoke rolling out the door when reloading. I've wondered if I could reduce the issue by eliminating the 90 degree bend, but for me it's a minor nuiscance not worth messing with.

 

[stoveliker]

I have a 27 ft and a 90 (and 2.5 ft horizontal). Works for me. But it depends on the stove too.

Also be aware that some stoves require (demand, suggest...) a certain vertical length before any bends. As using 45s will decrease that initial vertical length of your thimble does remain in its location, that may (or may not...) be an issue.

 

[Rob_Red]

I originally had a single wall setup going into the aforementioned masonry chimney. It worked well and I plan to replicate it with double wall for the new setup

 

[begreen]

The chimney will be 25ft off the T and the T will be 6 feet of the ground, the stove pipe will be about 30 inches or so. The class A is taking the place of a masonry chimney made of concrete chimney ring with clay liner, that was similar in specs, and was torn down.

The old setup used to draft very well and had a stove pipe using a 90. I was planning to replicate because I don't love the look of the 45's.

Also this setup is in my living room and I don't have negative pressure problems

That should draft well. I think it will be fine with a 90º in the stovepipe.

 

[Shrewboy]

I have a 27 ft and a 90 (and 2.5 ft horizontal). Works for me. But it depends on the stove too.

Also be aware that some stoves require (demand, suggest...) a certain vertical length before any bends. As using 45s will decrease that initial vertical length of your thimble does remain in its location, that may (or may not...) be an issue.

do you know why they suggest that? how long usually?

 

[stoveliker]

do you know why they suggest that? how long usually?

I don't know how long usually; I know it for my stove and have seen if in another manual as well. 2-3 ft

Why? I think (...) that it is to straighten out some turbulence before forcing the flow around a corner. Likely better flow (draft) and possibly less build-up.