Barometric Damper

[brenndatomu]

Does the baro damper’s injection of such a small amount of room air really cool the flue that much? It doesn’t take much of a “leak” to really spoil the draft. Properly adjusted, are we talking about 100 degree drop, 10 degrees?

There it is... it will only cool the flue enough to control the draft to the point of being the correct.
And I can't tell you how much it cools the flue...just that these warnings of creosote buildup after the BD have not been my experience...just the opposite actually...pipe seems a little cleaner after the BD...dilution maybe?
So for me, I see no real "risks" in having a BD...got to have creosote to have a fire...and my Kuuma makes none...and then even if there is a fire, a properly insulated flue should take it. A lower "risk" than running with high draft and ruining a $6k furnace...which isn't so much of a risk, as an eventuality.
The only downside I see is the need for makeup air to feed the BD...but not a huge issue in most basements.

 

[bholler]

There it is... it will only cool the flue enough to control the draft to the point of being the correct.
And I can't tell you how much it cools the flue...just that these warnings of creosote buildup after the BD have not been my experience...just the opposite actually...pipe seems a little cleaner after the BD...dilution maybe?
So for me, I see no real "risks" in having a BD...got to have creosote to have a fire...and my Kuuma makes none...and then even if there is a fire, a properly insulated flue should take it. A lower "risk" than running with high draft and ruining a $6k furnace...which isn't so much of a risk, as an eventuality.
The only downside I see is the need for makeup air to feed the BD...but not a huge issue in most basements.

Maybe in your furnace. But I rarely see any stove or furnace with a bd on it that doesn't have heavy glaze in the pipe and chimney even fancy modern kuumas

 

[brenndatomu]

But I rarely see any stove or furnace with a bd on it that doesn't have heavy glaze in the pipe and chimney even fancy modern kuumas

How many Kuuma chimneys have you seen?

 

[bholler]

How many Kuuma chimneys have you seen?

I service chimneys for 3. And many hundreds of other chimneys a year. And after wet wood dilution air is the second thing I look for when diagnosing creosote problems.


How many chimneys do you work on in a year?

 

[brenndatomu]

I service chimneys for 3. And many hundreds of other chimneys a year. And after wet wood dilution air is the second thing I look for when diagnosing creosote problems.


How many chimneys do you work on in a year?

No need to get your cockles up...I was just asking.

 

[brenndatomu]

Anything to add here @JRHAWK9 , or @lampmfg ?

 

[JRHAWK9]

Anything to add here @JRHAWK9 , or @lampmfg ?

boy, I guess I need to be taught what creosote looks like then, as apparently I have been confusing it for flyash all along. Here's after a full seasons worth of burning my very first year with my furnace WITH a BD installed the whole time. I've never seen creosote so white, but maybe the professional in the house can tell me about this type of creosote and why it's so dangerous...?



Now, here's where he better sit down. The past 2+ years I have been supplying <gasp> outside air directly to my BD to control my draft. I send ZERO heated inside air up the chimney to control my draft. I've seen temps as low as 10° being injected into my stove pipe at the BD about 30" from the collar of my furnace. I've even seen frost buildup on the tee of my OAK upstream of where it connects to my BD.

I've had zero signs of any condensation issues either in my chimney or in my stove pipe, none. The flue temps about 15" from the collar (before the BD) are anywhere from about 280° to 390° at cruise (pilot), depending on what level of burn (low to max) I keep my computer at. This setup all started as an experiment sometime in the middle of the burning season. I thought I was going notice some adverse effects, but I never did. I then waited to see what my chimney looked like at the end of the heating season. That too looked fine, so I went full speed ahead with it.

Now, with this setup, my chimney doesn't have that nice white fluffy creosote as pictured above, it's actually more along the lines of fluffy brown-black creosote. You know the creosote you can simply wipe with your finger as it falls to the ground as that annoying powder making it a pain to clean up.




Anyway, if the professional in the house could post up a link to educate me on the dangerous effects of this white and/or brown-black powdery creosote, I'd appreciate it.

 

[Highbeam]

boy, I guess I need to be taught what creosote looks like then, as apparently I have been confusing it for flyash all along. Here's after a full seasons worth of burning my very first year with my furnace WITH a BD installed the whole time. I've never seen creosote so white, but maybe the professional in the house can tell me about this type of creosote and why it's so dangerous...?

View attachment 268661 View attachment 268662

Now, here's where he better sit down. The past 2+ years I have been supplying <gasp> outside air directly to my BD to control my draft. I send ZERO heated inside air up the chimney to control my draft. I've seen temps as low as 10° being injected into my stove pipe at the BD about 30" from the collar of my furnace. I've even seen frost buildup on the tee of my OAK upstream of where it connects to my BD.

I've had zero signs of any condensation issues either in my chimney or in my stove pipe, none. The flue temps about 15" from the collar (before the BD) are anywhere from about 280° to 390° at cruise (pilot), depending on what level of burn (low to max) I keep my computer at. This setup all started as an experiment sometime in the middle of the burning season. I thought I was going notice some adverse effects, but I never did. I then waited to see what my chimney looked like at the end of the heating season. That too looked fine, so I went full speed ahead with it.

Now, with this setup, my chimney doesn't have that nice white fluffy creosote as pictured above, it's actually more along the lines of fluffy brown-black creosote. You know the creosote you can simply wipe with your finger as it falls to the ground as that annoying powder making it a pain to clean up.


View attachment 268663 View attachment 268664

Anyway, if the professional in the house could post up a link to educate me on the dangerous effects of this white and/or brown-black powdery creosote, I'd appreciate it.

When you say flue temps of 280-390 are you talking about flue gas temperatures or flue skin temperatures? It makes a big difference.

 

[brenndatomu]

When you say flue temps of 280-390 are you talking about flue gas temperatures or flue skin temperatures? It makes a big difference.

Internal

 

[JRHAWK9]

When you say flue temps of 280-390 are you talking about flue gas temperatures or flue skin temperatures? It makes a big difference.

Flue gas INSIDE the stove pipe on pilot, about 15" downstream of the collar, taken with the probe of a Thermoworks system. https://www.thermoworks.com/Smoke

 

[Highbeam]

Flue gas INSIDE the stove pipe on pilot, about 15" downstream of the collar, taken with the probe of a Thermoworks system. https://www.thermoworks.com/Smoke

That’s way down in “hold your hand on the single wall pipe temperature.” Those internal heat exchangers really strip the heat out before the smoke leaves the appliance.

 

[bholler]

Ok then I guess what I see the field all the time means nothing because if these 2 setups. Good to know.

 

[brenndatomu]

before the smoke leaves the appliance.

Smoke...what smoke?
Ohhh...you mean on cold startup...

 

[brenndatomu]

Ok then I guess what I see the field all the time means nothing because if these 2 setups. Good to know.

No, it just means the baros can't be categorically dismissed for all wood burners.
Your customers may be feeding those things wet wood, or doing lots of cold starts...or maybe they don't have an insulated flue?

 

[Highbeam]

Smoke...what smoke?
Ohhh...you mean on cold startup...

Okay, exhaust.

 

[jetsam]

View attachment 268661 View attachment 268662

Now, here's where he better sit down. The past 2+ years I have been supplying <gasp> outside air directly to my BD to control my draft. I send ZERO heated inside air up the chimney to control my draft. I've seen temps as low as 10° being injected into my stove pipe at the BD about 30" from the collar of my furnace. I've even seen frost buildup on the tee of my OAK upstream of where it connects to my BD.

I've had zero signs of any condensation issues either in my chimney or in my stove pipe, none. The flue temps about 15" from the collar (before the BD) are anywhere from about 280° to 390° at cruise (pilot)

I know this answer varies with the weather and stack height- but about what percentage of chimney exhaust on that system is flue gasses from the furnace versus intake from the barometric damper? It must be a small amount, implying that your stack isn't super tall?

I love it when people experiment with stuff. (My wife, less so.)

 

[JRHAWK9]

I know this answer varies with the weather and stack height- but about what percentage of chimney exhaust on that system is flue gasses from the furnace versus intake from the barometric damper? It must be a small amount, implying that your stack isn't super tall?

I love it when people experiment with stuff. (My wife, less so.)

Actually, I have ~30' chimney...BUT it's almost all inside a chase inside heated space. It's all new (on '14) ICC stuff as well.....so the higher Canadian spec stuff. The only part that is not in heated space is the part sticking out the top of the roof.

I'm guessing the colder air reduces the draft a bit therefore requiring the BD less air to bring the draft in check.

 

[sadpanda]

I think you are both correct...

I'm convinced that nearly every US/CAN stove install over drafts. Gases are not allowed to linger long enough in CAT to be completely burned so we end up with excessive creosote and significantly reduced CAT lifespan.

The baro damper is keeping draft in check, facilitating much more complete combustion. With little to no residual hydrocarbons, there is literally nothing to condense in the pipe.

I personally would still want some sort of manual control of the baro just in case... One chimney fire experience is enough for me.

 

[begreen]

No, it just means the baros can't be categorically dismissed for all wood burners.
Your customers may be feeding those things wet wood, or doing lots of cold starts...or maybe they don't have an insulated flue?

I think that BDs can be categorically dismissed for modern woodstoves which is where this thread started. There aren't many gasifiers in the freestanding stove market. Could there be exceptions? Possibly, but they would be an anomaly and not the rule.

 

[Highbeam]

I think that BDs can be categorically dismissed for modern woodstoves which is where this thread started. There aren't many gasifiers in the freestanding stove market. Could there be exceptions? Possibly, but they would be an anomaly and not the rule.

Aren’t all stoves gasifiers? Isn’t that what we burn? A wood furnace is just a stove in a box with an internal magic heat exchanger. Plus some electronic controls of the intake.

 

[Gearhead660]

boy, I guess I need to be taught what creosote looks like then, as apparently I have been confusing it for flyash all along. Here's after a full seasons worth of burning my very first year with my furnace WITH a BD installed the whole time. I've never seen creosote so white, but maybe the professional in the house can tell me about this type of creosote and why it's so dangerous...?

View attachment 268661 View attachment 268662

Now, here's where he better sit down. The past 2+ years I have been supplying <gasp> outside air directly to my BD to control my draft. I send ZERO heated inside air up the chimney to control my draft. I've seen temps as low as 10° being injected into my stove pipe at the BD about 30" from the collar of my furnace. I've even seen frost buildup on the tee of my OAK upstream of where it connects to my BD.

I've had zero signs of any condensation issues either in my chimney or in my stove pipe, none. The flue temps about 15" from the collar (before the BD) are anywhere from about 280° to 390° at cruise (pilot), depending on what level of burn (low to max) I keep my computer at. This setup all started as an experiment sometime in the middle of the burning season. I thought I was going notice some adverse effects, but I never did. I then waited to see what my chimney looked like at the end of the heating season. That too looked fine, so I went full speed ahead with it.

Now, with this setup, my chimney doesn't have that nice white fluffy creosote as pictured above, it's actually more along the lines of fluffy brown-black creosote. You know the creosote you can simply wipe with your finger as it falls to the ground as that annoying powder making it a pain to clean up.


View attachment 268663 View attachment 268664

Anyway, if the professional in the house could post up a link to educate me on the dangerous effects of this white and/or brown-black powdery creosote, I'd appreciate it.

This is what my pipe looks like with my T2, only dark brown/black. Believed it to be fly ash also. I have no damper, basically same as JRHawk9. Close to 30' tall all interior.

 

[brenndatomu]

I have no damper, basically same as JRHawk9. Close to 30' tall all interior.

Your draft has to be off the charts high!
No wonder its so clean...does the chimney do this sometimes?!

 

[brenndatomu]

dismissed for modern woodstoves

OK...but bholler made a blanket statement for all wood burners...that's how this one went in the weeds...

 

[bholler]

OK...but bholler made a blanket statement for all wood burners...that's how this one went in the weeds...

And I still stand by my statement based upon what I have seen. Even in your case where it is working well why would you not want a solution that controlled the draft without dilution air? It would allow for lower fluegas temps out of the appliance and would mean no makeup air would be needed for the bd.

 

[bholler]

I think you are both correct...

I'm convinced that nearly every US/CAN stove install over drafts. Gases are not allowed to linger long enough in CAT to be completely burned so we end up with excessive creosote and significantly reduced CAT lifespan.

The baro damper is keeping draft in check, facilitating much more complete combustion. With little to no residual hydrocarbons, there is literally nothing to condense in the pipe.

I personally would still want some sort of manual control of the baro just in case... One chimney fire experience is enough for me.

The statement that nearly every us/can stove is overdrafting is completely off base.