Does geography affect draft?

[enchant]

I've got a Jotul F400 Castine. Chimney extends 15' above top of stove, room is drafty, wood moisture is under 17%, outside temps in single digits. My draft sucks. I've discussed my problems here on the forum before, and I'm convinced that I've made all of reasonable changes that I can make to improve my situation. At this point, I've accepted that it is what it is and I live with it. I really don't want to revisit all of those issues again in this thread.

I just want to know if the geography around my house might be contributing to my draft problems. My house is on the side of a fairly steep hill. I'd estimate the average slope is 30 degrees, and it probably rises a good 70' before peaking. And there are plenty of tall trees adding to the height. Does geography enter into the equation?

 

[Doc C]

I've got a Jotul F400 Castine. Chimney extends 15' above top of stove, room is drafty, wood moisture is under 17%, outside temps in single digits. My draft sucks. I've discussed my problems here on the forum before, and I'm convinced that I've made all of reasonable changes that I can make to improve my situation. At this point, I've accepted that it is what it is and I live with it. I really don't want to revisit all of those issues again in this thread.

I just want to know if the geography around my house might be contributing to my draft problems. My house is on the side of a fairly steep hill. I'd estimate the average slope is 30 degrees, and it probably rises a good 70' before peaking. And there are plenty of tall trees adding to the height. Does geography enter into the equation?

Generally speaking yes. Geography can have an influence BUT it's typically an intermittent influence. Such as wind coming off a hillside causing smoke to blow back down a chimney. Or inversions settling in on areas especially around large lakes like the great lakes but that's intermittent as well.

If you are in a draw or essentially a canyon that is on a hillside then that should increase your draft in the evening and possibly slow your draft down during the day.

Think about using air currents when hunting. In the morning the air usually goes up and in the evening it goes up until a certain point in the evening when it switches and goes back down. Really makes elk hunting with a bow difficult!

But with all that being said, a proper chimney set up and burning practices should overcome 90+% of these intermittent issues.

So my guess would be that geography is not your issues if it's a constant problem.

Since you don't want to rehash any of the chimney setup issues you have fixed I will leave it at that.

 

[enchant]

Thanks, Doc C. That all makes sense. Appreciate the good info!

 

[ksmobile1]

I've got a Jotul F400 Castine. Chimney extends 15' above top of stove, room is drafty, wood moisture is under 17%, outside temps in single digits. My draft sucks. I've discussed my problems here on the forum before, and I'm convinced that I've made all of reasonable changes that I can make to improve my situation. At this point, I've accepted that it is what it is and I live with it. I really don't want to revisit all of those issues again in this thread.

I just want to know if the geography around my house might be contributing to my draft problems. My house is on the side of a fairly steep hill. I'd estimate the average slope is 30 degrees, and it probably rises a good 70' before peaking. And there are plenty of tall trees adding to the height. Does geography enter into the equation?

Yes it does, breeze or wind coming off hill could swirl and even cause downdraft let alone poor draft

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[Mark8]

I'm no expert, just a newbie, but I did see a draft fan that you can install on top of your pipe as a last resort, no one wants to spend a thousand dollars on a fan or use electricity, but as a last resort that might be an option, I have no experience with those fans so take my suggestion with a grain on salt and maybe others can comment.

 

[Doc C]

Yes it does, breeze or wind coming off hill could swirl and even cause downdraft let alone poor draft

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Right. But that's usually an intermittent issue and he has been dealing with this since at least 2016 if I remember the posts correctly in the past.

 

[sportbikerider78]

I live about 30' below a ridgeline. We get TONS of fast wind coming down the hill into the valley. I call it the train because of the constant roar that you can hear from the wind for days on end. Sometimes weeks.

I have a 15' or so flue and my pipe comes slightly above the roofline ridge of my house. On some days, it seems like I have a clog in the pipe somewhere or my air is not getting into the stove. I can't figure it out, but it is only about 10% of days.

Perhaps you should try measuring your barometric pressure around your property and in your home.

 

[ksmobile1]

Right. But that's usually an intermittent issue and he has been dealing with this since at least 2016 if I remember the posts correctly in the past.

[emoji106]

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[enchant]

I live about 30' below a ridgeline. We get TONS of fast wind coming down the hill into the valley. I call it the train because of the constant roar that you can hear from the wind for days on end. Sometimes weeks.

I have a 15' or so flue and my pipe comes slightly above the roofline ridge of my house.

There has been a lot of wind the past couple of days, but this problem happens constantly. The smoke doesn't come out like it's coming from a tailpipe (although I remember that happening with my old stove). It just gently wafts out when I have the door more than a couple inches open.

About the roof - perhaps my problem is there. The chimney extends 15' above the top of the stove and perhaps 10' above the roof it pokes through. But there is another roof on another part of the house that is taller than it. I'm guessing that that roof is 12-15' away from my stove chimney. The eves are maybe 3' below the top of the stove roof, but the peak of that roof is definitely higher - maybe as much as 5' higher.

 

[Marshy]

Is your chimney above your roofline a minimum or 3' and 2' taller than ajacent roof within 10' horizontally?

 

[enchant]

Is your chimney above your roofline a minimum or 3' and 2' taller than ajacent roof within 10' horizontally?

Here is a VERY rough drawing of my situation - certainly not to scale, but it'll give you an idea of what I've got. I stole the chimney part from your drawing.

 

[Doc C]

Here is a VERY rough drawing of my situation - certainly not to scale, but it'll give you an idea of what I've got. I stole the chimney part from your drawing.View attachment 219827

That's not exactly ideal but I'm pretty sure it's all within specs. Someone correct me if I'm wrong.

 

[Doc C]

Also I'm assuming the mountain is on the right side of your drawing?

 

[Marshy]

Here is a VERY rough drawing of my situation - certainly not to scale, but it'll give you an idea of what I've got. I stole the chimney part from your drawing.View attachment 219827

How many feet of pipe between cap and roof, and from stove to roof?
Draft is largely driven by flue temperature. Obviously wind and direction of wind will affect draft. Have you measured the draft on a calm day with the stove operating on high?

 

[bcrtops]

A good chance you have the "stack" effect going on. Do a google search. Often happens when the peak of house is taller than the top of the chimney, causing the house itself to act as a better "chimney". Has to do with Neutral Pressure Plane (NPP).

 

[enchant]

Also I'm assuming the mountain is on the right side of your drawing?

No, the mountain is to the left.

 

[enchant]

How many feet of pipe between cap and roof, and from stove to roof?
Draft is largely driven by flue temperature. Obviously wind and direction of wind will affect draft. Have you measured the draft on a calm day with the stove operating on high?

Ok, I've created another image with a better representation of my setup. I'm not sure how to "measure" the draft. I just know that if I'm down to coals, I can open the door and everything is fine. But let's say I've got a fire going and my carefully laid out wood pile shifts and now I don't have decent air getting between the splits. I need to open the door to reposition a split. I open the door a couple of inches to get the draft going at maximum velocity. Then I slowly open the door enough to get tongs to the split. Maybe I'll have five seconds, maybe it'll happen immediately, but smoke is going to waft out. So I mostly do my best to just crack the door and try to adjust as best I can with a simple poker.

 

[begreen]

Based on the last image, it looks like the issue is not geography, it's the installation. The Castine needs strong draft, especially if rear-vented. For starters I'd change it to top vent, then soften the 90º turn with a pair of 45s and an offset, something like this. That should help, but the chimney may need extension too.



Is there an insulated 6" liner in the chimney?

 

[enchant]

Yes on the insulated liner. The guy who rebuilt our chimney insisted on it.

As far as changing the Castine to a top vent, it sounds like a logically terrific idea, but I have to believe that this is going to be a very expensive upgrade, right? I wish I was aware of this option (and the potential draft issue) before I purchased the stove. As far as extending the chimney, I really don't want to do that. I added 4' on to the original chimney and that didn't make any difference whatsoever. Any more and I'll probably have to install guy wires. It's looking ugly enough as it is.

 

[begreen]

Yes on the insulated liner. The guy who rebuilt our chimney insisted on it.

As far as changing the Castine to a top vent, it sounds like a logically terrific idea, but I have to believe that this is going to be a very expensive upgrade, right? I wish I was aware of this option (and the potential draft issue) before I purchased the stove. As far as extending the chimney, I really don't want to do that. I added 4' on to the original chimney and that didn't make any difference whatsoever. Any more and I'll probably have to install guy wires. It's looking ugly enough as it is.

Not too expensive. The flue collar just gets reversed. Then there will be the cost for a pair of 45 elbows and the connector.

I've owned and run the Castine. It's a beautiful stove and a strong heater, but its shallow firebox and large door make it prone to smoke spillage and draft sensitive. Even with a straight-up 20' flue our stove spilled smoke when it got above 50º. This was because I had to rear-vent it, then to a 90º pointed up in order to move the stove further into the room to increase wall clearances. Unfortunately, IMO this is not the best choice for this setup. An easy breathing top vent stove would perform better.

 

[enchant]

Actually, isn't this a top exit as it's set up?

 

[Marshy]

Actually, isn't this a top exit as it's set up?

View attachment 219836

Yes,.

Have you considered not opening the door with a partially burnt load?

 

[begreen]

Actually, isn't this a top exit as it's set up?

View attachment 219836

Yes, the drawing showed rear exit. but this flue collar is in the top exit position.

 

[begreen]

The issue is that the Castine really needs at least 16' of flue and that is straight up. A 90º elbow slows down the flue gases and effectively reduces the chimney height about 2 ft. for each 90º turn. The Castine is not too happy running on a flue system that is effectively 13ft..

 

[enchant]

Have you considered not opening the door with a partially burnt load?

That would make too much sense.

Yes, and that's what I do. I'd just kinda like to know why I have so much trouble, but chances are that a real fix would probably be either outside of my financial options, or would require me to have the 8th wonder of the world as a chimney. I'm fine with not opening the door, though.

And thanks to everyone for all of the helpful information. I may not have solve my problem, but I know more than I did a day ago.