The importance of chimney length

[rwilly]

My new stove calls for 15’ of chimney, I’ve got about 5’ in the house and was going to put about 7’ on the roof.

How much will that affect the performance of the stove?

Thanks

 

[Jan Pijpelink]

What I have learned on this site is, that the length of the chimney is crucial for the draft. The taller the chimney, the better the draft. I had a minimum size chimney for one of my stoves. Added 4 feet and what a difference.

 

[jetsam]

It Depends™. If your stove is an easy breather and the run is straight, you could be okay.

If the stove is picky, you could have poor draft, especially in shoulder season (think hard to start, smoke in the stove room, poor low burns).

If the stove is picky and the install has multiple 90s or other bad stuff, it could be pretty unuseable.

Even if you fall into the "it's okay" category, you could benefit from a few extra feet of flue.

 

[Gotrek]

I have about 17 feet(14 indoor 3 outside) and the stove worked great. Then the installer realized he made a mistake and added two 15degree elbows inside and then the stove worked just OK. I added 2 feet more this year and its backs to working great!

On the flip side I have 11 feet in the shop(3 inside the rest in the attic/outside) on an older smaller stove and that stove works great with that.

Sent from my SGH-I337M using Tapatalk

 

[begreen]

My new stove calls for 15’ of chimney, I’ve got about 5’ in the house and was going to put about 7’ on the roof.

How much will that affect the performance of the stove?

Thanks

What stove?

 

[SuperJ]

Apparently using double wall inside helps your draft by keeping the flue gases hot longer. Especially, if you're on the short side make sure you go double wall to the stove.

 

[begreen]

Yes, double-wall stove pipe is an asset. My friend had an Endeavor on a 12' chimney with three 90º turns and single-wall stove pipe. It spilled a little smoke whenever you opened the door and secondary combustion was poor unless it was cold outside. This is their sole source of heat so having it work well when it's 55 outside was important. We removed all the stove pipe and replaced it with double-wall, moved the stove location and used a 45 to eliminate one elbow. The stove was replaced with a Summit. Voila, no more smoke spillage.

 

[cd36]

Yes, double-wall stove pipe is an asset. My friend had an Endeavor on a 12' chimney with three 90º turns and single-wall stove pipe. It spilled a little smoke whenever you opened the door and secondary combustion was poor unless it was cold outside. This is their sole source of heat so having it work well when it's 55 outside was important. We removed all the stove pipe and replaced it with double-wall, moved the stove location and used a 45 to eliminate one elbow. The stove was replaced with a Summit. Voila, no more smoke spillage.

I agree that a double wall pipe is good to have, but it's tough to use your example as proof of that. You literally changed everything about that install except the person loading the stove and the house wrapped around it.

Sent from my LG-H812 using Tapatalk

 

[begreen]

When draft is weak, it sometimes takes a combination of options to come up with a good solution that works at all temps. This was a particularly troubled installation.

 

[rwilly]

What stove?

It’s an Endeavor, straight pipe right through the roof, no bends.
I think it will be fine, I don’t really want 10’ or more of pipe sticking out of the roof.

 

[ohlongarm]

My new stove calls for 15’ of chimney, I’ve got about 5’ in the house and was going to put about 7’ on the roof.

How much will that affect the performance of the stove?

Thanks

I guess it depends on the stove,my BK calls for 12 ft minimum I believe. i'm just there no probs that I can tell.

 

[begreen]

It does depend on the stove. Many secondary tube stoves have a fairly long supply path for the secondary air, some with a few 90º turns in it too. Other stoves like Enviro, some Morso and PE (and perhaps others) have a short and direct tube that helps the stove work better on a shorter chimney.

rwilly, the setup may work, especially once temps get colder. In milder weather and on low pressure days it may work or it may spill a bit of smoke on opening the stove door and secondary combustion may be weak. You'll have to try it out and let us know. Be sure to brace the chimney at the 5' point of exit from the roof and the 10' level if an extension has to be added.

 

[Ashful]

I guess it depends on the stove,my BK calls for 12 ft minimum I believe. i'm just there no probs that I can tell.

You’d be the rare bird, if your chimney is so good that you can’t stall your BK on it. Bottom line, BK’s can be turned way down low, to the point where they’ll stall almost any chimney. Exactly how far you can turn it down, in any outdoor weather condition, is a function of draft.

So, yes... I’m sure you can run your BK on 12 feet of pipe, but I’m also very sure you could successfully run it at a lower setting on 20 or 30 feet of pipe.

I have two BK’s, both on insulated 6” liners, one being 15 feet and the other 30 feet. Guess which one stalls first, when it gets warm out?

 

[Twolfe278]

Willy,

I have an endeavor also. I might be wrong, but I thought the TOTAL height of stove + chimney needed to be 15'.

I am right at 14.5' from floor to chimney top with no bends and I have an excellent draft. Burning right now in 47* weather and feeling cozy.

 

[begreen]

Yes, I have a friend with a straight-up flue on an Endeavor that is about the same height. It works ok. Worth a try.

 

[firesideshawn]

With the install manual of my fireplace they include from the bottom of the fp in that run length, so its possible (or likely) twolfe is correct

 

[rwilly]

Yup, Twolfe is correct.
I re-read the manual, and it’s 15’ from bottom of unit to top of chimney.