my reverse flow build comments suggestions please

[daveomak]

About the inlet I have 14 square inches with out subtracting the butter fly valve I need 11 that should be sufficient don't you think ??

Should be, yes.... Soooooooo..... The exhaust may be a little restrictive due to the ID..... what's the FB/CC opening and area under the RF plate.... We have to figure out where the restriction is....

 

[shane58722]

The area of 4.5 by 13 shape of a football the end opposite is 2.5 by 13 rectangle shape I see that end is way small help calculate the firebox end

 

[shane58722]

Okay I found how to calculate an ellipse an came up with 45 square inches does this make sense?

 

[lendecatural]

Your football is right at 40 sq-in. and the 2.5 x 13 is a little small. You can calculate the football by dividing the 4.5 in half and adding two segment areas together. So the 2.25 ED segment height and 13" cord gives 19.9 square inches for each half football and added together you are at 40".

http://www.1728.org/circsect.htm

How big of a fire did you have going and did you use charcoal, lumps, or sticks? Did you run the lower intake wide open and the upper vent wide open when you were trying to get it warmed up? Is your firebox door sealed air tight? 

 

[lendecatural]

That's close enough on the firebox end, I think you are good there. It won't be hard to cut 3/4 to 1" off the end of the RF plate. Usually I see upper vents being the small one and the lower vent being larger on fireboxes. Yours are the other way around but the total hole size of the butterflies is good. You may need to get a really hot fire going, leave the lower vent wide open and only crack the top vent and see what happens after you get the RF plate trimmed back. If none of that works, time for a bigger pipe for the exhaust.....

 

[daveomak]

Is the RF plate located similar to the drawing......


... click on pic to enlarge ....

Shane.jpg

• daveomak
• May 21, 2014

 

[shane58722]

I was just using charcoal birqutts I was thinking of making the exhaust 3in or should I wait and see what happens after the rf end is bigger

 

[lendecatural]

How high is the RF plate above the bottom of the cook chamber to answer Dave's question on post 26? 

 

[shane58722]

An inch or 2

 

[lendecatural]

You are good under the RF plate if it is at least 5.5 inches above the bottom of the CC. I would trim the RF plate an inch, get a hot fire going, open the lower vent all the way and crack the upper vent and see what happens before you go to a bigger exhaust. Lump charcoal will burn hotter than charcoal if you can get your hands on some.

 

[shane58722]

Would it be bad if I trimmed it back more than an inch like 3 or 4 inches

 

[daveomak]

LenDecaturAL

How high is the RF plate above the bottom of the cook chamber to answer Dave's question on post 26?

An inch or 2

Your RF plate is positioned where the RED line is ?????????????? This is not making any sense to me....

Shane.jpg

• daveomak
• May 21, 2014

How high is the RF plate above the bottom of the cook chamber to answer Dave's question on post 26? 

 

[shane58722]

Yes it is where the red line is

 

[lendecatural]

$hit, that's not good, I thought you meant it was an inch above the top of the "football".....

 

[daveomak]

Yes it is where the red line is

Well we found the problem..... the RF plate needs to be ABOVE the FB/CC opening.... then you will have good air flow through the CC... Soooo, move it above the football shaped cut out and be sure it's sealed to the sides of the CC..... May need a new piece of metal..... Dave

 

[lendecatural]

Or you could buy one of these....

http://www.auberins.com/index.php?m...ducts_id=398:c60af45995467049261384b52baa0e56

 

[daveomak]

I'm afraid of pressurizing the FB and overheating it AND/OR having the heat and smoke blowing out the FB door, or out the butterfly valve if they don't seal tight.... BUT I could be wrong.... been wrong before and will be again.....

But if it works as it should..... That would be good, very good.......

 

[shane58722]

Lol I'm very sorry Dave I missed something but my rf plate is above the opening not where the red line is I'm sorry

 

[shane58722]

Also I'll ask again can my rf opening opposite the fire box be to big ?

 

[daveomak]

Also I'll ask again can my rf opening opposite the fire box be to big ?

NO.....