About those flue dampers.

[Whitespider]

There's some points being missed, and I'm startin' my own thread on this subject rather than keep runnin' other threads down sidetracks.

Argument - Modern stoves don't need or require a flue damper because they don't leak and the combustion air inlet controls the fire.

That may be true... but only if draft is within the design tolerances of the stove. Modern (secondary combustion) stoves are designed and engineered to work properly within a certain draft tolerance window. Typically they have two air intakes, primary and secondary; the relationship between those two is designed to work properly within that specific window. Although some users have claimed they can completely shutdown the air intake(s) on their modern EPA stoves, they must be missin' something... for a stove to pass EPA testing it must run (meaning the fire does not go out) at the lowest available user setting without smoldering the fire too much (particulate emissions must meet the regulations). So, in fact, a modern stove does leak... there's a built-in leak to insure compliance. Nearly every installation manual states the acceptable upper and lower draft tolerance... and, if required, most recommend a barometric damper to adjust said draft (the "suck" acting on the firebox... the "over-fire" draft).

OK, so let me ask a question... what is a flue damper??
Answer... a device installed in the flue pipe and used to adjust "over-fire" draft by reducing it (a damper cannot increase it, it can only reduce what exists).
Well boys, a barometric damper is a damn flue damper... so saying a modern stove does not need a flue damper flies in direct contradiction to most installation manuals/manufacturer recommendations (depending on conditions). Sayin' that every modern (EPA) stove, in every installation, does not need a flue damper is friggin' ridiculous... even the manufactures say they will need one (for peak performance) if draft ain't correct.

The two most common flue dampers are the manual "key" damper, and the (often recommended) semi-automatic barometric damper... they both accomplish the same thing, just in different ways. One reduces "suck" on the firebox by restricting pipe opening, the other reduces "suck" on the firebox by creating a leak in the pipe. Neither is ideal and without drawbacks. The manual "key" damper requires a bit of user thought, know-how, and yes, a learning curve... and an idiot can screw it up. The semi-auto barometric damper introduces cool air into the flue and pulls more air from the space being heated (that air must be made up from cold outside air)... and it does require periodic inspection, maintenance and adjustment. They both have their positives over the other also. One gives you instantaneous, total, variable control... the other handles the adjustment for you, but removes the convenient variable control. Don't overlook that convenient variable control... for getting a fire started, changing firewood species, even for a quick blast of heat when wanted.

What type or style of flue damper you opt for is a personal choice. What influences that choice could be any number of things. For example, if your chimney opening is subjected to constantly changing wind direction and speed, a baro may be a better choice so as to avoid constant damper adjustments. On the other hand, if your draft is relatively constant, and you prefer more control, you may find the manual damper more to your liking.

But either way... sayin' that modern secondary combustion stoves never require a flue damper is patently false. The manufacturers recommend flue dampers... they recommend the supposedly "fool-proof" type, but there ain't nothing "fool-proof", never has been, never will be. The fact is, unless the conditions are near perfect, a new-fangled stove will likely benefit more from a flue damper than an old style stove will. Unless conditions are perfect, your choice isn't whether-or-not to install a flue damper... the choice is which style to install.

The performance of any wood-fired appliance may be improved with a flue damper... but you'll never know if ya' don't try it.
There ain't no friggin' magic, never has been, never will be.
*

 

[Chris-PA]

Although some users have claimed they can completely shutdown the air intake(s) on their modern EPA stoves, they must be missin' something... for a stove to pass EPA testing it must run (meaning the fire does not go out) at the lowest available user setting without smoldering the fire too much (particulate emissions must meet the regulations). So, in fact, a modern stove does leak... there's a built-in leak to insure compliance.

"Some of those users" know quite well how their stoves work, and that you are once again making things up to suit your narrative. My stove has no fixed secondary air intake, and as I doubt you have ever seen a US Stoves Magnolia 2015 in person I suggest you refrain from making further erroneous statements.

How hard is it to figure out how a welded steel box with an air inlet works?

All of this is irrelevant to the question the OP asked.

 

[nathon918]

All of this is irrelevant to the question the OP asked.

WS is the OP of this thread...it has nothing to do with the other thread which is why he posted his own

I'm startin' my own thread on this subject rather than keep runnin' other threads down sidetracks.

however I do agree that there are stoves out there that can have the air shut to the point of starving the fire...mine being one of them, I can shut it down so far that it smokes like a damn steam engine...I believe the operators manual would "make up" for the air adjustments, as it likely tells the operator how to adjust the settings to be EPA compliant? im just guessing though

 

[Chris-PA]

WS is the OP of this thread...it has nothing to do with the other thread which is why he posted his own

Yes, you are correct - I did not see that this was a second thread. My error.

 

[laynes69]

I agree. They aren't required if they fall within a recommended draft by the manufacturer, otherwise they are needed. A modern wood unit introduces alot more air than the old airtights, but they regulate the air in specific places. If the draft isn't controlled, when fully shut they can run away. I used a barometric damper which was required by the manufacturer of our woodfurnace, until I decided to reduce the amount of intake in both primary and secondary ports. Now it's controllable. There are quite a few stoves that even with an overdraft can be controlled manually, but many can't. When they design a unit to test on a 15' stack, and it's installed on a 30' chimney, there will be problems.

 

[olyman]

and using a "auto" dampner,,introduces waaay cooler air into the exhaust pipe,, cooling the gases,,and potentially increasing the hazard of more creosote..............

 

[Whitespider]

...you are once again making things up to suit your narrative. My stove has no fixed secondary air intake, and as I doubt you have ever seen a US Stoves Magnolia 2015 in person I suggest you refrain from making further erroneous statements.

What?? Did you think this thread was directed towards you and your stove??
If your Magnolia don't fit 100% with what I posted, that makes it "made up" or "erroneous"??

Nope, I've never seen a Magnolia... but I've looked at a lot of them, downloaded even more manuals when looking to replace the old smoke dragon, and then again when I was lookin' to replace the "stovace". Not all of them are designed and built the same... and that's why I used terms such as "typically", "nearly", "most", "recommended" and "may".

Nothing I posted was framed as an "absolute"... but yours sure comes across that way.

OK, so your stove doesn't have separate "intakes" for primary and secondary air. My use of the descriptive "two air intakes" was possibly somewhat confusing at best (call it erroneous if you choose)... my meaning was that the air is channeled into the firebox as separate primary and secondary supplies designed to work together. Whether-or-not there are actual separate intakes makes no difference to my meaning, or to the function of them as a system. For example, my PE has two separate openings in the bottom of the firebox, which is enclosed within the base... but technically it only has a single "air intake" in the rear of the base. Different designs use different methods for separating and channeling the respective air supplies... but they still work as a system, regardless of how the separation is accomplished, or how the air is controlled.

By-the-way, I couldn't help but notice your Magnolia is only rated at 65% combustion efficient... how can you possibly get any heat output from such an outdated design??

 

[olyman]

What?? Did you think this thread was directed towards you and your stove??
If your Magnolia don't fit 100% with what I posted, that makes it "made up" or "erroneous"??

Nope, I've never seen a Magnolia... but I've looked at a lot of them, download even more manuals when looking to replace the old smoke dragon, and then again when I was lookin' to replace the "stovace". Not all of them are designed and built the same... and that's why I used terms such as "typically", "nearly", "most", "recommended" and "may".

Nothing I posted was framed as an "absolute"... but yours sure comes across that way.

OK, so your stove doesn't have separate "intakes" for primary and secondary air. My use of the descriptive "two air intakes" was possible somewhat confusing at best (call it erroneous if you choose)... my meaning was that the air is channeled into the firebox as separate primary and secondary supplies designed to work together. Whether-or-not there are actual separate intakes makes no difference to my meaning, or to the function of them as a system. For example, my PE has two separate openings in the bottom of the firebox, which is enclosed within the base... but technically it only has a single "air intake" in the rear of the base. Different designs use different methods for separating and channeling the respective air supplies... but they still work as a system, regardless of how the separation is accomplished, or how the air is controlled.

By-the-way, I couldn't help but notice your Magnolia is only rated at 65% combustion efficient... how can you posibly get any heat output from such an outdated design??

View attachment 419496

bing! budda ding!!!

 

[nathon918]

and using a "auto" dampner

what are you trying to dampen? hard to believe you have that much velocity through your stack to need a dampner (shock absorber)

 

[olyman]

what are you trying to dampen? hard to believe you have that much velocity through your stack to need a dampner (shock absorber)

heya troooool, how yah doing??? talked to your brother BA lately?? how about overclock???? also,,keep your filthy insinutions about sexual matters to your foul brain self...........or del your brother???

 

[nathon918]

heya troooool, how yah doing??? talked to your brother BA lately?? how about overclock????

we're all the same person aren't we?

 

[Chris-PA]

What?? Did you think this thread was directed towards you and your stove??

The part of your post I quoted in comment #2 was the part I responded to, and the only part I intended to address (heck, I wouldn't have read it if I had not gotten confused as to which thread it was). As I'm about the only one here who has made the claim that I can "shutdown the air intake(s) on my modern EPA stove", it's pretty clear who you had in mind. You can try to wriggle out of it now, but I am not missing anything about how that stove works, and it does not "leak" in the sense that I can stop down the inlet and come very close to putting out an overfired stove in a couple of minutes.

Further, it is connected to a 30' insulated 6" flue running up an interior masonry chimney with only a couple of gentle bends. The flue is sealed to the top of that masonry chimney at the top so it stays warm. It draws very well and has no damper, so lack of draft will not be an explanation as to why I can shut it down. Thus the quoted part of your statement is BS, which is why I responded to it.

As to the 65% - whatever. I heat my house on a small number of cords with no central heating system as backup. I have no excessive coaling problem and my wood does not get incinerated on the top and buried in ash at the bottom. Thanks to the excellent draft of the flue I get great secondary combustion with big jets of flame coming out of the secondary air manifold.

Not only isn't magic, it isn't even difficult.

 

[stihly dan]

The part of your post I quoted in comment #2 was the part I responded to, and the only part I intended to address (heck, I wouldn't have read it if I had not gotten confused as to which thread it was). As I'm about the only one here who has made the claim that I can "shutdown the air intake(s) on my modern EPA stove", it's pretty clear who you had in mind. You can try to wriggle out of it now, but I am not missing anything about how that stove works, and it does not "leak" in the sense that I can stop down the inlet and come very close to putting out an overfired stove in a couple of minutes.

Further, it is connected to a 30' insulated 6" flue running up an interior masonry chimney with only a couple of gentle bends. The flue is sealed to the top of that masonry chimney at the top so it stays warm. It draws very well and has no damper, so lack of draft will not be an explanation as to why I can shut it down. Thus the quoted part of your statement is BS, which is why I responded to it.

As to the 65% - whatever. I heat my house on a small number of cords with no central heating system as backup. I have no excessive coaling problem and my wood does not get incinerated on the top and buried in ash at the bottom. Thanks to the excellent draft of the flue I get great secondary combustion with big jets of flame coming out of the secondary air manifold.

Not only isn't magic, it isn't even difficult.

That must be nice. I wish my old stove had that ability. I have a chimney as high and not interior, and I could not control the draft with my epa stove. I had key damper, heat recovery in flue, reduced the top of the chimney, and partially blocked the intake air inlet. With all that I still had to be very wary of over firing when the secondary's are running. Hard to get going, impossible to stop it from going. Worst year of my heating life, thank God it happened on the warmest winter ever. I think it was a good stove just not the right application. I'm also not saying a non epa is better either, just giving my experience.

 

[Chris-PA]

That must be nice. I wish my old stove had that ability. I have a chimney as high and not interior, and I could not control the draft with my epa stove. I had key damper, heat recovery in flue, reduced the top of the chimney, and partially blocked the intake air inlet. With all that I still had to be very wary of over firing when the secondary's are running. Hard to get going, impossible to stop it from going. Worst year of my heating life, thank God it happened on the warmest winter ever. I think it was a good stove just not the right application. I'm also not saying a non epa is better either, just giving my experience.

I've wondered what that would be like, and it sounds quite frightening. I've also wondered how well a flue damper would work to stop it, as when I close the inlet down it's pretty small. If the door gasket is getting sloppy you can see a tendril of flame from every place that a little oxygen get past it. The damper would have to fit pretty well to stop it down the same.

I have a second smaller stove on a slightly shorter flue that is otherwise the same spec, and no flue damper. It has secondaries that are always open, but I have never over fired it. It seems like the secondaries are restrictive enough that if I close the primary all the way it just kind of peters out. It is smaller though so heat energy being released at a lower rate inside.

 

[stihly dan]

The part of your post I quoted in comment #2 was the part I responded to, and the only part I intended to address (heck, I wouldn't have read it if I had not gotten confused as to which thread it was). As I'm about the only one here who has made the claim that I can "shutdown the air intake(s) on my modern EPA stove", it's pretty clear who you had in mind. You can try to wriggle out of it now, but I am not missing anything about how that stove works, and it does not "leak" in the sense that I can stop down the inlet and come very close to putting out an overfired stove in a couple of minutes.

Further, it is connected to a 30' insulated 6" flue running up an interior masonry chimney with only a couple of gentle bends. The flue is sealed to the top of that masonry chimney at the top so it stays warm. It draws very well and has no damper, so lack of draft will not be an explanation as to why I can shut it down. Thus the quoted part of your statement is BS, which is why I responded to it.

As to the 65% - whatever. I heat my house on a small number of cords with no central heating system as backup. I have no excessive coaling problem and my wood does not get incinerated on the top and buried in ash at the bottom. Thanks to the excellent draft of the flue I get great secondary combustion with big jets of flame coming out of the secondary air manifold.

Not only isn't magic, it isn't even difficult.

I have noticed on my furnace with a BDR, That when I am liting
That must be nice. I wish my old stove had that ability. I have a chimney as high and not interior, and I could not control the draft with my epa stove. I had key damper, heat recovery in flue, reduced the top of the chimney, and partially blocked the intake air inlet. With all that I still had to be very wary of over firing when the secondary's are running. Hard to get going, impossible to stop it from going. Worst year of my heating life, thank God it happened on the warmest winter ever. I think it was a good stove just not the right application. I'm also not saying a non epa is better either, just giving my experience.

I've wondered what that would be like, and it sounds quite frightening. I've also wondered how well a flue damper would work to stop it, as when I close the inlet down it's pretty small. If the door gasket is getting sloppy you can see a tendril of flame from every place that a little oxygen get past it. The damper would have to fit pretty well to stop it down the same.

I have a second smaller stove on a slightly shorter flue that is otherwise the same spec, and no flue damper. It has secondaries that are always open, but I have never over fired it. It seems like the secondaries are restrictive enough that if I close the primary all the way it just kind of peters out. It is smaller though so heat energy being released at a lower rate inside.

I've wondered what that would be like, and it sounds quite frightening. I've also wondered how well a flue damper would work to stop it, as when I close the inlet down it's pretty small. If the door gasket is getting sloppy you can see a tendril of flame from every place that a little oxygen get past it. The damper would have to fit pretty well to stop it down the same.

I have a second smaller stove on a slightly shorter flue that is otherwise the same spec, and no flue damper. It has secondaries that are always open, but I have never over fired it. It seems like the secondaries are restrictive enough that if I close the primary all the way it just kind of peters out. It is smaller though so heat energy being released at a lower rate inside.

I have noticed on my wood furnace that when lighting from cold with the ash drawer open, when its time to close it the BDR will be closed and as soon as I close the drawer the BDR opens. Which tells me I get higher draft with a smaller opening on my furnace. This is also true when the automatic modulating damper for primary air goes full closed, now only air is through secondary's and the BDR will open more.

 

[stihly dan]

I have no idea what just happened there. ROBOTS?

 

[Whitespider]

As I'm about the only one here who has made the claim that I can "shutdown the air intake(s) on my modern EPA stove", it's pretty clear who you had in mind.

No... actually you're not the only one... in fact, you weren't even on my mind when I posted that.

A couple years back, when I was trying to make the "stovace" work and throwin' hissy-fits over it, there were two or three guys that made wild claims about literally killin' the fire in seconds and stating (as fact) the new-fangled fireboxes were purposely designed to to run better with ultra-high draft and other such. When I presented actual facts disputing what they claimed was fact... well... I was an azzhole.

The truth is... I've never doubted your claim of complete control... I've never believed there was an absolute, or a one-size-fits-all.
The truth is... that's always been my point... there ain't no friggin' magic‼
How many friggin' times do I haf'ta say that?? I've never been the guy claiming "all", "always", "every time", and whatnot.
*

 

[stihly dan]

all", "always", "every time", and whatnot.

But you use the word NEVER a lot.

Says the guy from the bandstands.

 

[Whitespider]

But you use the word NEVER a lot.

No way‼
I never... err... well
*

 

[lindnova]

WS - I agree 100% with your first post.

I have a PE Spectrum with a 25 ft stack. It overfired regularly until I modified(bent) the damper stop tab. Works great now. On cold nights I can turn it down to low on a good full cruising load(the new low completely covers the primary hole and secondary still has some air). Burns clean all night and have good coals in the morning - I use the glass as a signal if it is burning dirty. If warmer outside leave the damper open some. There is a learning curve for everything.

My options were to burn small fires or warping infernos; I tried turning it down sooner, but it would always eventually get to nuclear. This was on dry bur oak. If I put cherry or box elder in it was instant nuclear. Wet wood would smoke and burn poor, but even that would overfire on low after a while - if it kept burning. Solutions were to install a damper or modify the intake. I chose the former.

I bet if I had a 10 ft chimney this stove would be fine in stock mode. There is not a one size fits all program for this.

I have never had more than 1 cup of soot from cleaning the chimney. Had the stove 2 seasons and cleaned 2 times. Each time it was so clean that it really wasn't necessary, but I would rather check it than risk a fire. I suppose I should climb up the roof to check it this spring after going all winter this year (burned about 2 cords). I am confident it still is fairly clean.