30-NC flue length

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ColoMack

New Member
May 25, 2014
13
Colorado
Hello posted a few weeks ago about the Englander 30-NC and I have decided this is the stove I want. Before I purchased one I downloaded the instruction book and I was reading through it tonight to see if there was any information I might like to know before I placed my order. Something did catch my attention and that is they recommend that the flue length does not exceed 25'. Is this common? My current flue length is 23' (stove will be in my basement so this is the reason for the long distance) and I just ordered another foot of triple wall to get to my 10 foot 2 foot rule. so this brings my grand total is 24' just under the recommended length. I may need one more foot but I wont know until I can get up to my roof and measure to see if my clearance is good. If that is the case it will put me right at the recommended 25'. Is this a problem? I am guessing if it is too tall it will effect the draft?
 
It might over draft which can be controlled with a stack damper or key damper. i don't think it will be a problem but i would probably put in a damper
 
Be patient and you should get a lot of replies from those w basement installs and 25+' chimneys. Many have really strong drafts and if it is not a through house system need a little flu primer to start a cold stove. Many use a key damper to moderate the vacuum effect of a tall chimney system. This will be exaggerated or lessoned if you are going straight up or if you have turns in the pipe.

If I remember correctly the NC30 was lab tested with a 16' system so some need to make adjustments if going above or stopping below this but it all relates to your system so you wont know until its up and running.
 
Thank you for the replies.

Yes my system is straight up and inside the house until it exits the roof. I will look into a damper. Any specific one that works well with this stove?
 
A key damper is a pretty basic piece. Just get the one that fits your 6" pipe. It may not be needed at all, but it wouldn't hurt to have in the system for those "special" weather days. Lots of folks have these things stuffed into basements. You will be just fine.
 
Your local hardware store probably has a 6" key damper in stock. When installing it, keep it at least a few inches away from the pipe joint so that it can rotate freely without snagging on the 3 screws at the joint.

If you have double-wall stove pipe you need to buy a special 6" section with the damper already installed.
Single wall - Damper.jpg Double wall - damper double wall.jpg
 
Are you measuring flue height from stove top to cap? It is better to be too long than to be too short.
 
I'm running a 30 and its 23' from stove top to cap for me. Runs fine. It does pull a strong draft and if I load the wood improperly (lots of air space) it can run hotter than desired. What I've learned is that the most important thing is super dry firewood. It lights off easier and is easier to damper down and still have a good fire.
 
Are you measuring flue height from stove top to cap? It is better to be too long than to be too short.
yes top of stove to cap. Just an estimate factoring in the 36" pieces of triple wall then measured from top of stove (current stove) to support box. In the last week I ordered the additional chimney piece, stove thermometer, and my new 30-NC ( very excited, cant wait). I cannot find any dampers locally so I will have to order online. I spent the morning cutting firewood until it got too hot out. its hard to believe I am preparing for cold weather when its 100 degrees out!

Thank you for the help everyone.
 
I see you are in Colorado, what's you're elevation? how old is the structure? is it well sealed up?

remember when dealing with a stove the whole house as well as outside factors such as elevation all are relevant.

the taller flue will not be quite as "rowdy" at a higher elevation as it would be near sea level, so being close to the max recommendation isn't as big an issue the higher ASL you are burning at.

at higher altitude air is thinner so it lacks the "mass" of sea level air, draft is generated by energy possession at the molecular level , less molecules means less exited particles so less mass and momentum creating a bit less draft. its crazy when you think about it but its actually a factor
 
draft is generated by energy possession at the molecular level , less molecules means less exited particles so less mass and momentum creating a bit less draft. its crazy when you think about it

Hmmmm. WIll have to think about that one. I believe that the thinner air both inside and outside of the flue require the need for a longer flue or more hearth heat to drive the draft. I don't know if I would call that energy possession on the molecular level. Density sounds like a good term but maybe the same meaning in this context?
 
Hmmmm. WIll have to think about that one. I believe that the thinner air both inside and outside of the flue require the need for a longer flue or more hearth heat to drive the draft. I don't know if I would call that energy possession on the molecular level. Density sounds like a good term but maybe the same meaning in this context?



yeah thats kinda what i was getting at, his concern being that if he were close to max recommended length that there might be an overdraft issue. what i was meaning with the post is that with the thinner air the "density" as you say which is probably a better term to use, being less there are less actual particals per cubic unit of measure to be energized and thus carry the heat energy so the amount of air transiting will be less. this means that the potential for overdraft would be lessened , especially when the lesser oxygen per cubic unit of measure present is factored in a taller stack would probably help more than hurt
 
yeah thats kinda what i was getting at, his concern being that if he were close to max recommended length that there might be an overdraft issue. what i was meaning with the post is that with the thinner air the "density" as you say which is probably a better term to use, being less there are less actual particals per cubic unit of measure to be energized and thus carry the heat energy so the amount of air transiting will be less. this means that the potential for overdraft would be lessened , especially when the lesser oxygen per cubic unit of measure present is factored in a taller stack would probably help more than hurt

Thanks for that Mike, I think it clears things up.
 
It seems that barometric dampers are never installed for wood/pellet stoves, but are routinely recommended by boiler manufacturers. Is there a reason for this, especially in a basement installation? It would seem to control the draft to right where you want it to be.
 
It seems that barometric dampers are never installed for wood/pellet stoves

They cant be used for pellet because pellet stove vents are actually slightly pressurized which would blow smoke and fly ah out the baro damper. They should not be used for wood because they introduce cool air into the smoke stream which reduces draft (which is what they are meant to do) and increase creosote buildup.
 
They cant be used for pellet because pellet stove vents are actually slightly pressurized which would blow smoke and fly ah out the baro damper. They should not be used for wood because they introduce cool air into the smoke stream which reduces draft (which is what they are meant to do) and increase creosote buildup.

Plus when you do get a chimney fire the baro damper opens fully to turn your flue into a blast furnace.

Oh and they would look pretty dumb atop a woodstove in the living room.
 
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Looks are the very least of the problems with a baro damper on wood stoves
 
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