Chimney extension?

[cmonSTART]

Something I was pondering tonight... My draft for my stove is less than ideal. It's a through the wall style chimney with about 15 feet of triple wall stainless prefab vertically outside. Inside there's a couple feet of horizontal stove pipe to reach where the stove has to sit, and then about 3 foot of vertical single wall going in to the stove. I plan on redoing the interior stuff this fall to take out some horizontal, but how much effect would another three foot section of chimney have on it? I would have to add some support poles going to the roof, but it might help a bit. Anyone have any idea of how much it will help?

Trying to make our wood supply do as much as it can...

 

[begreen]

First I would work on the interior. If you can convert to double wall off the stove and be sure that the horiz. run is pitched up hill at least a quarter inch per foot, you will be on the right path. If there still needs to be improvement, then add another 3 ft. of pipe.

 

[cmonSTART]

Here's another question about the 1/4 inch per foot slope on the horizontal. The stove pipe snaps into the thimble at a 90 degree angle to the wall, making it horizontal. There is a little flex there so I could just flex it downward a tad to achieve the desired slope, use furnace cement etc. Is there are problem with doing this?

 

[begreen]

Yes, take advantage of the flex at the thimble, within reason. Smoke does not like to go sideways and definitely doesn't want to go downhill.

 

[kjklosek]

Are you able to use 2 45's instead of one 90 ell?

That way you eliminate the horizontal all together.

J.P.

 

[cmonSTART]

That's what I'm planning on doing. I won't be able to eliminate the horizontal completely. I still have to come out a bit to maintain my 18" from combustibles.

 

[zzr7ky]

Hi - Another 3' of insulated on the outside would be the next step after these fine suggestions. I'd do the inside work and try it in warm weather. OK in warm weather should be fine in cold weather.

Good Luck,
Mike P

 

[begreen]

That's what I'm planning on doing. I won't be able to eliminate the horizontal completely. I still have to come out a bit to maintain my 18" from combustibles.

I like using the 2-45's too. Go double wall, you will get better draft and reduce clearances down to 6".