Draft supporting chimney cap

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JA600L

Minister of Fire
Nov 30, 2013
1,288
Lancaster Pennsylvania
Hi guys,
I've been reading a lot about different chimney caps. I know some are designed to stop wind from down drafting.

I'm just wondering if there are caps that actually increase chimney draft?

I'm just trying to get things optimized, thanks.
 
Yes there are some but they typically come with some issues. Are you having trouble?
 

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Hello
What about a draw collar?
They do not increase draft they only help to jump start draft that is hard to get going
 
It depends on the situation. Often just adding a few more feet of chimney can make a notable improvement in draft. Most of the time a Vacu-Stack cap is recommended to improve draft and solve wind related downdraft.
 
They do not increase draft they only help to jump start draft that is hard to get going

And add a pain in the ass to cleaning the pipe.
 
This is my setup.

The stove is 6" from the hearth wall with the required heat shield. The double wall stove pipe runs vertical for 3 feet to the first 90. It has about a 2 feet horizontal run to a 90 at the chimney liner. The liner is 6" uninsulated in an outside masonry chimney. It was installed by a professional and I was told insulation wouldn't fit. The vertical chimney run is 25 feet. The only real problem I get is some smoke when opening the door of the Ideal Steel.

The house is, a 70's rancher with plenty of gaps. I did air seal and insulate the attic along with spray foaming gaps.

I don't think I need a lot of draft help, just a little extra boost.

I'm also on my 2nd year of being on the 3 year plan. I will be burning lots of 2 year old ash this winter
 
The liner is 6" uninsulated in an outside masonry chimney. It was installed by a professional and I was told insulation wouldn't fit.
Not a very good pro then. A vacustack may help you out but they are a real pain to clean. and they will only help if you have consistent wind to draw through it. Is the chimney tall enough with regard to the surroundings? at 25' it should be plenty of height. Insulation would help also.
 
I agree about the pro. I wish I would have known about busting the clay to install insulation before I had it done. He didn't even suggest it.

The chimney is the highest point of the house other than the tv antenna.

I do feel that maybe some of my wood was not fully cured last year. This year it will be no question about that.
 
Can you swap out the 90s for 45s? ,may help some. At 25 feel, that thing should draft pretty well.
 
Smoke spillage is different than hard starting or low heat that can come from under-seasoned wood. I haven't heard of the IS being draft sensitive. It sounds like that setup should work fine. Does the smoke spillage occur when it is below freezing outside? Is this only at start up, or even on a reload?

One thing to check is to be sure the tee is tightly capped on the bottom. Any leakage is not going to help draft. If this occurs all the time, even in cold weather, I would contact Woodstock. Perhaps there is something not quite right with the stove? Or it could be the location of the chimney relative to the local terrain. Is it worse when it's windy?
 
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It has been more of a shoulder season issue. When it is very cold out I don't seem to have too much trouble. The stove has a smoke flap, but the door opening is very large. It measures 17''x12.5''. When the door is opened in the first notch there is no spillage. Opening the door fully is where I get some spillage.

Will any gaps in joints in the stove pipe going to the T-connector cause this kind of issue?
The stove pipe kit is Selkirk from Lowes. I do recognize that it is not a top quality product. I have also been researching and checking prices for adding 45 degree elbows.

Maybe my best option would be to order a new higher quality double wall stove pipe kit and get it professionally installed?

I am willing to spend money if its justified.
 
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Sealing the joints if they have gaps may help. Going to double-wall sounds like a good plan. It will help keep the flue gases hotter. One thing to check - be sure that horizontal section is pitched uphill toward the thimble at least 1/2" between the elbow and the thimble.
 
The product I have now is double wall. I'm just saying that it does not appear to be a high quality kit. I will make sure there is a 1/2'' rise.
 
It should be decent then. Check to be sure the pipe is sealing well at the flue collar. If not, put some furnace cement in the gaps.
 
Selkirk has a cap that has a flat top and a concentric outside ring rather than the the wide open screened type that is so common. I am at just about the bottom of a fairly good hill with towering trees behind me and on one side, so I get crazy swirling issues and outside down drafts ( as indicated by start up smoke) at times - with this cap I have had no issues.NC30 stove on main floor about 15ft flue- double wall to ceiling then triple insulated rest of way all Selkirk from box store straight up. Wood furnace in basement so around a 25ft or so of flue ( flex lined and insulated masonary) this one has the cold start reverse draft problem, reloads occasionally will spill it has the screen type cap.
 
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