Question About All Important Draft

[REF1]

As important as draft obviously is, I have a question. Does this mean if you put a stove in the back yard, with no flue pipe whatsoever, you would not be able to burn a load of wood in it? What would, or would not happen? Obviously you would be able to burn a load of wood in it. So, what is the scientific necessity of strong draft? It seems to be the necessity of getting air through multiple passageways in newer stove designs. In both old and some new stove designs air inlets are just right there, an opening on the door, or top of the stove or something. Open the draft, look inside the stove, see the flames.

I can see how strong flue sucking is necessary to draw air through all the tunnels into the firebox in newer stoves for cleaner glass, and now secondary combustion.

 

[DAKSY]

So, what is the scientific necessity of strong draft?

How about to evacuate the byproducts of the combustion
process out thru the connector pipe & the chimney instead
of back into the house?

 

[Backwoods Savage]

Generally the higher the chimney the more draft you will have.

Try sometime burning wood outside and observe how it burns with no wind and then how it burns when a gust of wind hits the fire. In a stove, it is like those gusts of wind hitting the fire except that it is all contained in a small box. But when you reload a stove and turn up the draft you can see the flames really burning high, similar to that outdoor fire that has been hit by a gust of wind. And that is why we have draft controls also. We do not want that high of a flame for normal burning; only when getting the wood starting to burn. Then we cut off that gust of wind.

Also the chimney is required to release the smoke and gasses above where we live. Has anyone gone past one of the OWB when smoke is right down to ground level? Remember that most of that is being released only 10' off the ground. No wonder people are complaining about these things.

 

[begreen]

As important as draft obviously is, I have a question. Does this mean if you put a stove in the back yard, with no flue pipe whatsoever, you would not be able to burn a load of wood in it? What would, or would not happen? Obviously you would be able to burn a load of wood in it.

Not really. Several stoves would not burn well at all under these conditions, especially if they have a rear exit flue. If one tried this experiment without any pipe on many modern stoves, the fire would smolder and smoke would billow out if the stove door was opened. It takes some draw to get the smoke to reverse around the baffle.

So, what is the scientific necessity of strong draft? It seems to be the necessity of getting air through multiple passageways in newer stove designs.

I can see how strong flue sucking is necessary to draw air through all the tunnels into the firebox in newer stoves for cleaner glass, and now secondary combustion.

Correct. The stove is only half of the burning system. The flue is the equally important other half. Here are some helpful articles for understanding the importance of a proper flue.

https://www.hearth.com/econtent/index.php/articles/chimneys_an_unexact_science/
http://www.woodheat.org/chimneys/aboutchimneys.htm
http://www.woodheat.org/chimneys/chimneys.htm

 

[REF1]

Obviously the reason for a flue or chimney is to release smoke, etc. The point of my question is to address current draft systems in stoves, not the flue itself, though obviously bends and turns come into play in the flue.

In my case I am addressed in the manual to have at least 13' of release. I have 17-18' and less than substantial air intake to start fires and keep smoke in the stove when the door is opened. So, my conclusion would be the system designed to pull air into the stove and send it out is not as good as another stove meant to address EPA standards. I have wondered why. My concerns of pull through the system will be better addressed when I have the next stove in place using the same flue system.

If I had to compare this current system with older stoves I have owned, the older, simpler systems put air into the firebox much better. Draft is only as good as the stove allows it.

 

[begreen]

Agreed, a full 17-18' liner should draw quite well from the description. First thing to check to be sure the flue cap screen clean. Then confirm that the horiz. section is heading uphill towards the chimney. Has it been confirmed that there is no obstruction or kinking in the liner? Another thing to check is for leaks. Air infiltration can greatly reduce a flue's effectiveness. Common locations for leaks are at the stove flue collar, at the thimble and at the cleanout tee on the liner.

 

[Dave_1]

REF1,

might want to add this link to BeGreen's list;

"A Buyer's Guide to Chimney Relining"

http://www.woodheat.org/chimneys/bplinerusers.pdf

 

[vvvv]

Obviously the reason for a flue or chimney is to release smoke, etc. The point of my question is to address current draft systems in stoves, not the flue itself, though obviously bends and turns come into play in the flue.

In my case I am addressed in the manual to have at least 13' of release. I have 17-18' and less than substantial air intake to start fires and keep smoke in the stove when the door is opened. So, my conclusion would be the system designed to pull air into the stove and send it out is not as good as another stove meant to address EPA standards. I have wondered why. My concerns of pull through the system will be better addressed when I have the next stove in place using the same flue system.

If I had to compare this current system with older stoves I have owned, the older, simpler systems put air into the firebox much better. Draft is only as good as the stove allows it.

With an EPA stove, the combustion air is preheated & stratified [when the primary air is closed]so it results in a better mixture for the woodgas to burn.

 

[BrotherBart]

Air just simply has to be drawn farther and into more places in a modern stove. In most modern stoves the primary and secondary air inlets are at the bottom rear of the stove. To get to the air wash/primary air inlets into the firebox it has to travel up, around the top of the firebox and then down the glass and into the fire. A lot longer trip than old stoves that just let the stuff in at the bottom front and straight into the fire.

The air for the secondary tubes has to come in, travel up to the manifolds and into the tubes and be drawn out into the fire.

Lot of distance and the only thing that can get the air where it needs to go is the chimney draft.

 

[Battenkiller]

Draft is important even in the older designs. That's why you don't want to try to transfer every last bit of heat out of your system. Some needs to go up the flue to generate draft. With no draft at all, an airtight stove will basically go out. There is always some degree of draft in a stove, just like in the aforementioned campfire, but it is rather low compared to a having a proper flue. With only very marginal draft (short or no chimney), intake air will have very low velocity and burns will be sluggish and inefficient.

 

[vvvv]

Draft is important even in the older designs. That's why you don't want to try to transfer every last bit of heat out of your system. Some needs to go up the flue to generate draft. With no draft at all, an airtight stove will basically go out. There is always some degree of draft in a stove, just like in the aforementioned campfire, but it is rather low compared to a having a proper flue. With only very marginal draft (short or no chimney), intake air will have very low velocity and burns will be sluggish and inefficient.

Draft can be excessive & result in wasted heat up the chimney. The height of the chimney itself creates draft. What's a barometric damper?

 

[laynes69]

A barometric damper will open when a set draft exceeds the setting. This in return dilutes the draft of the unit causing a constant draft. They are used when there is an overdraft. We run one on our furnace but its required in the manual to keep a set draft.

 

[ansehnlich1]

I've read right here on hearth.com where some will "burn off" the new paint smell of their new stove in the driveway or outside before bringing the stove indoors for installation, and have seen pipe connected to the stove outside so as to give it a little draft to burn properly.

I'm not aware of any experiments to date but my bet is that if you loaded the Oslo with a fresh load of paper, kindling, and splits, lit that bad boy, had all the doors closed and the primary air wide open, you would compete, if not outsmoke, the nearest OWB in the neighborhood!

I ain't convinced the load would burn at all under those conditions, it would probably snuff out....

 

[BrotherBart]

My old insert is sitting behind the woodpile playing meat smoker. And a great smoker it is. With ten feet of pipe on top it is a smoking mess when burning.

And when I did this burn-in on the driveway I had a hell of a time getting the stove up to temp. The door had to be cracked open the whole time.