Was having draft problems...not now NC30 redneck engineering

[MAD MARK]

NC30 was having draft issues on this warm wet evening 60°F . Decided to try some Kaowool on the lower 4 foot of single wall. Surface temps at 18" went from ~200°F to about ~325°F. No draft issues now.

The 1" Kaowool might be a bit much. But in essence, from my understanding, I just basically made this double wall pipe+ the lower 4'.

What am I missing from an understanding point of view? Hack job for sure, but experimental on my part short term 1 burn.

 

[enduring]

We have a tornado watch here in Central Iowa. it was very warm a bit ago, now the wind has picked up and the temp is dropping.

I am a novice. Let me ask a few questions: if you keep the flue insulated, than it keeps the exhaust hotter, helping keep the draft up to speed? What was the symptoms that you didn't have a good draft?

We have a tornado watch here in Central Iowa. it was very warm a bit ago, now the wind has picked up and the temp is dropping. I doubt we get a tornado in our area. We live in a magic area, to the east of the river. Growing up I lived just up the hill from the same river in Des Moines, Iowa. My mother told me that legend was that you didn't get tornados in "the fork of a river". Well after growing up I realized we lived "near" the fork of the Des Moines and Raccoon Rivers, but not in the forked area. Our storms mostly come from the southwest, hit the river, then I think it changes the weather/temps for a time, before it picks up the umph again, and carries on. Weather is amazing. I can see that flue operations are similar.

 

[SculptureOfSound]

not a bad idea, just watch out the micro dust/fibers released from kaowool are believed to cause lung cancer.

 

[bholler]

NC30 was having draft issues on this warm wet evening 60°F . Decided to try some Kaowool on the lower 4 foot of single way. Surface temps at 18" went from ~200°F to about ~325°F. No draft issues now.

The 1" Kaowool might be a but much. But in essence, from my understanding, I just basically made this double wall pipe+ the lower 4'.

What am I missing from an understanding point of view? Hack job for sure, but experimental on my part short term 1 burn.

View attachment 258740

There are clearly some problems for long term like the zip ties exposed insulation etc. But as an experiment looks good to me.

 

[MAD MARK]

If I haven't got anything from Kaowool yet then I won't ever. chit flies everywhere at work.
I are
Going to see how this acts tonight.

It's strange right now with STT at 425°F and yet the pipe is at 375°F. Still drafting strong too but so far so good. Might convince me to get some double wall.

 

[MAD MARK]

And just in case anyone wondering, my flue height from top of stove to top of cap is 11'5". I'm quite under the 15' normal. But, this is helping a lot.

 

[Highbeam]

I’ve got 10’ of of single wall above my nc30 and I lose over 100 degrees of surface temperature in that distance. Lots of heat loss which is a double edged sword, good for heating the space but bad for draft and creosote.

I’ve thought about upgrading to double wall with a key damper since I’ve got 9 feet of class a above the single wall.

 

[NickW]

Interesting solution Mark. You helped me greatly a couple of months back when I installed my NC30. I'll just say I have no real draft issues, but I've got 7' of double wall and 20' of insulated liner. Today was very still and foggy and 45 degrees. When I let it get cold it didn't draft great, but a quick little fire to warm things up and it's fine. I was able to get the double wall at one of the local big box stores for a few hundred dollars, which was way better than the mess of the online ordered liner...

 

[coaly]

If you're asking why it helps; You're raising the average internal flue temperature.

What you're doing is increasing the draft by raising the flue temp without the heat loss through the pipe to the indoor air. Draft is the measurement of rising gasses creating a low pressure area in chimney, pipe and stove. The greater the temperature difference, the greater the pressure differential between inside and outside of flue. The warmer it gets outside, the hotter the flue needs to be inside for enough temperature differential to cause enough draft. The key is average internal temp, not just connector pipe or flue temp as it drops near the top, that increases net draft causing a lower pressure in the stove, allowing atmospheric air pressure to PUSH air with oxygen into the stove. A low pressure area moving over also has less air pressure to push into the stove, so even more temperature differential between inside and outside of the flue is needed to decrease the flue, pipe and stove internal pressure even more.

 

[begreen]

The solution is to switch to double-wall stovepipe and add 4' of chimney pipe to the chimney.