newbie questions, Gibraltar reviews????

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Lightning
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Post by Lightning » Wed. Nov. 14, 2018 6:42 pm

ratherbeflying wrote:
Wed. Nov. 14, 2018 4:24 pm
regardless of primary air setting??
Like Franco said, the primary air setting will dictate the heat output. Actually you are looking at it backwards. Let's say you have a mano reading of -.04 and 400 degrees on the stove with the primary half open. If the draft gets stronger, let's say -.06, the stove will get hotter at that same half open primary air setting. That's the beauty of a steady draft. You will learn what heat output you will get at particular primary air settings without it being influenced by a variable draft. In essence, the draft directly relates to the velocity and volume of primary air entering the stove at a given primary air setting.


 
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Post by ratherbeflying » Wed. Nov. 14, 2018 9:22 pm

Lightning wrote:
Wed. Nov. 14, 2018 6:42 pm
Like Franco said, the primary air setting will dictate the heat output. Actually you are looking at it backwards. Let's say you have a mano reading of -.04 and 400 degrees on the stove with the primary half open. If the draft gets stronger, let's say -.06, the stove will get hotter at that same half open primary air setting. That's the beauty of a steady draft. You will learn what heat output you will get at particular primary air settings without it being influenced by a variable draft. In essence, the draft directly relates to the velocity and volume of primary air entering the stove at a given primary air setting.
ok that makes sense.. what happens if i leave the primary at half open but adjust the baro to open sooner, does that also make the stove run cooler? and vise versa make the baro not open until later make the stove run hotter?

 
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Post by Lightning » Thu. Nov. 15, 2018 3:03 pm

ratherbeflying wrote:
Wed. Nov. 14, 2018 9:22 pm
ok that makes sense.. what happens if i leave the primary at half open but adjust the baro to open sooner, does that also make the stove run cooler? and vise versa make the baro not open until later make the stove run hotter?
Yes, that is all correct :)

 
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Post by ratherbeflying » Fri. Nov. 16, 2018 12:49 pm

so draft speed is directly related to stove temp?? lol what temp would a .03 draft be compared to .06... better question what should i set my baro to open at if i want my stove around 450-500

 
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Post by Lightning » Fri. Nov. 16, 2018 1:19 pm

That part is all trial and error :) You just gotta pay attention for a few weeks and see what primary air opening gives you the heat output that you want.

A -.03 will give you a lower heat output than -.06 at the same primary air opening.

 
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Post by ratherbeflying » Fri. Nov. 16, 2018 1:59 pm

if i set it to open at .03 and at half throttle the baro is opening to keep the draft at .03, what would happen if i opened primary air more? the baro would open more and the stove temp wont change??

 
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Post by Lightning » Fri. Nov. 16, 2018 2:46 pm

ratherbeflying wrote:
Fri. Nov. 16, 2018 1:59 pm
what would happen if i opened primary air more? the baro would open more
Yes.
ratherbeflying wrote:
Fri. Nov. 16, 2018 1:59 pm
and the stove temp wont change??
No, the stove temp will change.

The baro and primary combustion air are independent of each other "control wise" but they do directly influence each other.

If you open the primary air more, you will get more heat since more combustion air can feed the fire. The baro will hold the draft steady at -.03, the stove temp will reach a plateau, and the baro door may or may not (but probably will) open more to compensate for the additional heated air mass going up the chimney. This extra heated air mass would normally increase the negative draft pressure which would increase volume/velocity of primary combustion air and make the stove even hotter yet. The baro prevents that from happening.

See, clear as mud haha. It's not really that complicated. Once you see all the moving parts in action and learn thru trial, it'll all make good sense to ya :)


 
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Post by Lightning » Fri. Nov. 16, 2018 4:05 pm

In an effort not to confuse things further lol, the main bone of combustion air is to understand that it is pressure driven. Warm gases enter the chimney which are lighter and want to rise. This creates a vacuum in the stove, albeit a very tiny vacuum. We like to refer to this pressure difference as "draft". Draft is what drives combustion air into the stove. Pressure wants to move from areas of high toward/into areas of low. Increasing that pressure difference forces air into the stove faster, decreasing it will of course slow it down. Keeping it consistent (with a baro) takes that variable out of the equation which makes the stove easier to manage, more well behaved and more predictable at the combustion air setting that you choose.

 
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Post by ratherbeflying » Fri. Nov. 16, 2018 8:51 pm

totally get it.. but...... that would mean the baro could also be used to change the temp... meaning i could have the primary air open 75% of the way but the baro open at .02 and the stove would run at -.02 draft which sounds like it should be somewhere in the 300 degree range or less, when without a baro installed if i had the primary air open 75% the stove would be screaming at 600 degrees... does that sound close to logical?

 
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Post by Lightning » Fri. Nov. 16, 2018 9:53 pm

Yes, that hypothetical situation is absolutely valid.

 
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Post by CapeCoaler » Fri. Nov. 16, 2018 10:07 pm

Bottom line...
A baro helps control the draft by minimizing a variable...
Your draft can certainly exceed the baro capacity with high winds...
And the stove temp will increase...
The only way to reasonably maintain a constant stove temperature...
On a hand fed stove...
Is to use a bi-metallic controlled air inlet...
Or sit by the stove and manually adjust the air inlet control yourself...

 
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Post by Lightning » Sat. Nov. 17, 2018 1:56 pm

You gotta have a hell of a wind storm to overwhelm the baro. Even if so, the baro will greatly mediate the draft surges.

 
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Post by ratherbeflying » Sat. Nov. 17, 2018 2:58 pm

awesome!! you guys recommend any decent baros, manos, and bi-metal thermostat control kits?? honestly would love all three i think id save alot of coal!

 
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Post by Lightning » Sat. Nov. 17, 2018 4:57 pm

Field Controls RC baro. It normally comes with a cowl that straps over the pipe and you need to cut a hole in the pipe to use it. I would skip all that silly fiddling and use a "T" to fit the baro into, it looks much better too.

Manometer wise, the Dwyer Mark II model 25 is a fluid type gage. I've used one in the past, loved it. I'm currently using a Magnehelic model 2000-00 that I found on eBay cheap.

Adding a bi metal thermostat may take some ingenuity. The baro and mano will be a HUGE help to you :)

 
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Post by CapeCoaler » Sat. Nov. 17, 2018 8:15 pm

You gotta have a hell of a wind storm to overwhelm the baro. Even if so, the baro will greatly mediate the draft surges.
In the winter it does blow here on The Cape...
And I have pegged open a baro on my old Mark II...
Went to a DS machine with the Bi metalic only...
And would be able to maintain stove temps spot on...
Just need to adjust stove temp to outside temps...
He seemed to be thinking the baro would be the control device...
I like thinking of them as a variable reducer...


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