How much secondary air is enough or too much? What if it was adjustable?

True. I'd like control of that though.....to actually lessen the amount of air being allowed into the stove via all inlets/intakes, not just the primary.
Purely for investigative purposes.

 

Are you absolutely sure about that? If you have a link to something technical that says that it would be great. I can't wrap my head around that. If it didn't cut down or slow air flow, every fire would rage out of control, either at the bottom of the stove, or the top. My primary is controlled, but the secondaries are fully unregulated.

I'm not sure on air flow dynamics, but I would think to a certain point, air holes being restricted might boost velocity. But eventually it would hit a wall. Kind of the same reason the air intake and exhaust on your car aren't 1/2" or 3/4" tubes or pipes. If it never restricts air, you should never be able to stall a fire, and running the stove would be easier, just warm it up and throttle primary air full back. If an elbow in the chimney can restrict flow, surely making air run through a smaller hole must as well?

 

For investigative purposes, my secondaries fired less intense, and slower, and longer, and at about a 40 degree angle downward with 33% less cowbell. Which doesn't jive with same volume of air. At least not to my non engineer brain.

 

Interesting thread.

My VC Dutchwest is a cat stove. About 5yrs old.

There are air controls for both the primary firebox and the cat itself.

I usually burn with the primary air open full.

Now, the cat air is the puzzle. The control is a round dial, with no markings. Clockwise closes, counter opens.

I've always burned with the thing open a couple of turns, figuring for the cat, more is better. I've never expetimented with it. The manual just makes note of the air control, without any real guidelines for its use.

Any cat stove vendors or anyone support them here have any input?


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Might need to dumb that down a bit for my brain to grab it!

 

My first stove circa 2002 was set up with both primary and secondary air control- sorely miss the secondary control on today's stoves. I could get almost a ten hour burn from a full load. Unheard of now with something the size of a NC13. It was a tube stove made out west somewhere - Company declined to spend bucks on EPA so shut that part of business down.I still have it will have to look at the name on it.

 

The secondary air intake on the 30 is 2", I believe, and the primary is 3". Less air, but I almost never completely shut down the primary so probably similar volume on a normal burn.
Hmmm
I did move the aluminum tape back over about 1/2 of the secondary intake a couple days ago, and notice it needs more primary to produce the same kind of secondary burn. The tertiary (doghouse) air is still doin' it's thing.
Overall, I don't think much has changed but the air adjustment.
Back to our regularly scheduled burn method.

 

But your chimney is still "drafting" the same when you "slide" you lever in.................all you're doing is causing the air entering the stove (via the draft from the chimney) to enter the "burn box" in different locations!! Doesn't matter if secondary and tertiary/doghouse air is regulated or not!!!

 

I thought that was the point I was trying to convey.
Evidently, I didn't succeed.
However, as stated in a previous post, if all intakes were regulated, there would be less air being drawn in if I chose.
It would probably burn like crap though.
I'm done messing with it, and the tape is coming off the secondary intake. That little experiment didn't change burn time.

 

When your primary adjustment is wide open you are flowing a lot more air through the stove (in total) than with it closed, the secondary air system tends to be long with lots of turns and kinda restrictive, so with the primary wide open you may be 90% primary, and 10% secondary...whereas when closed it may be just the opposite, 10% primary, 90% secondary...but as I said before, the total air flow is way down...that is part of the reason you see the STT go way up when you close down the primary air...yeah once secondary combustion starts, the firebox temp goes up, but also the hot flue gasses have more contact time with the stove top due to the lower velocity (less CFM through the stove and up the chimney)

 

I'm gonna disagree.....................and think about this some

 

Feel free...once you do a little more research you will find I'm right.
Ever look at your chimney with the air wide open vs closed down? (early in the burn, when you can still see the steam)
I have, and there is obviously much more volume/velocity coming from the chimney when the primary air is wide open...

 

I believe the same, when primary is throttled back, there is less total air flow through the stove, and the percentage running through the secondaries is increased in relation to the primary.

I also believe the air intakes (6 holes on my stove) for the secondaries eventually limit or slow the air flow, although still flowing more than needed. This may cause the whistling I hear under crazy wind/hard draft.

I know some think that air is air, and it will flow no matter what, but let me ask this. If you duct tape a 4" pipe to your face and breathe for a minute, then do the same with a garden hose, then do the same with a straw, do you think the outcome would be different?

 

Bingo!

 

Now I just need to figure how much airflow I need to cut on the top end of the secondaries to achieve just an extra " random percentage" of settle down.

 

Yeah, that is kind of a trial and error thing, I think it will be different on every model stove, and every install...I was able to cut about 1/3 off on my wood furnace secondary air inlets with no ill effects...it didn't extend burn time a ton...but it did extend it out to the point of being noticeable.
If you go too far it will make your coals last forever...but that doesn't help you if its really cold out and you need maximum BTUs...at that point a lil more primary air will do more good that anything...

 

Ah jeez, another experiment I'm gonna' feel obligated to try.......not.