# fire help (reverse flow)



## rhaugle (May 23, 2020)

Hi all...
2 days ago I got my reverse flow smoker (custom made), and have been trying to get it heated up for its first burn in. I am having a hell of a time just keeping the fire healthy. I guess im not sure how big of a fire i should try to make? I have tried charcoal briquets, which left tons of ash (had these on an elevated grate for ash to fall through. Today I have tried lump charcoal just sitting in the firebox (no grate). I bought some wood from facebook, which I was told would be seasoned, and it wasn't... pretty wet still. So I bought a few bags of B&B post oak... split it up and cut a few pieces down... how big should my logs be? I have been trying to split down to about a coke can, or smaller, and 10 inches or less in length.  I am using a charcoal chimney to light the (now) lump, and doing 2 round of it to get a good coal bed going.

the CC is 4ft long and 2ft in diameter. the smoke box is about a foot and a half, also by 2ft round. Picture attached.. Im already frustrated and its only been 2 days! I cant keep this fire healthy/clean.. HELP!  running the FB door and stack vent wide open


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## rhaugle (May 23, 2020)

Also, I have been running the firebox door wide open, and the stack wide open also.


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## MikeFromTexas (May 23, 2020)

I recommend you run the calcs from this forum on the pit dimensions. Specifically look at the FB/CC area and the smoke stack. Looks like a mighty small diameter smoke stack and long.


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## Alphonse (May 23, 2020)

Put your numbers in a pit builder/design calculator.  Just looking at the photo I am betting you find the stack is too small.


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## sawhorseray (May 23, 2020)

That's a pretty nice looking stick burner! Check out some YouTube videos to get started. I don't hardly ever use charcoal in my offset anymore, just start a bunch of splits with a weed torch and let that burn down to a nice clean bed of hot coals, then add splits as needed. I also run my SQ36 with the door open, anywhere from a crack to a few inches, it's how I like to control the heat in the CC. RAY


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## rhaugle (May 23, 2020)

MikeFromTexas said:


> I recommend you run the calcs from this forum on the pit dimensions. Specifically look at the FB/CC area and the smoke stack. Looks like a mighty small diameter smoke stack and long.





Alphonse said:


> Put your numbers in a pit builder/design calculator.  Just looking at the photo I am betting you find the stack is too small.




its a 4"diameter stack.. havent run the calculator yet.. but if it is too small, how do I "fix" this..? Add another stack?


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## rhaugle (May 23, 2020)

Ok.. measured and calculator-ed.... 
FB size differential - 131% ( so i think thats good)
4" chimney recommended length is 37", mine measures 40"
"number of intakes: - .12 not sure on this?


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## rhaugle (May 23, 2020)

Link to BBQ Pit Calculator


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## rhaugle (May 23, 2020)

MikeFromTexas said:


> I recommend you run the calcs from this forum on the pit dimensions. Specifically look at the FB/CC area and the smoke stack. Looks like a mighty small diameter smoke stack and long.





Alphonse said:


> Put your numbers in a pit builder/design calculator.  Just looking at the photo I am betting you find the stack is too small.




not sure if the link will show my numbers, but I typed out 3 of them... chimney is tall enough according to the calculator


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## rhaugle (May 23, 2020)

sawhorseray said:


> That's a pretty nice looking stick burner! Check out some YouTube videos to get started. I don't hardly ever use charcoal in my offset anymore, just start a bunch of splits with a weed torch and let that burn down to a nice clean bed of hot coals, then add splits as needed. I also run my SQ36 with the door open, anywhere from a crack to a few inches, it's how I like to control the heat in the CC. RAY




ive watched tons videos sadly.. they are all pretty similar haha. are you familiar with the calculator? what do you think of my numbers?


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## MikeFromTexas (May 23, 2020)

rhaugle said:


> not sure if the link will show my numbers, but I typed out 3 of them... chimney is tall enough according to the calculator



that calculator you showed (Feldon’s)  isn’t what I was referring to. There is a tutorial on the forum





__





						Reverse Flow Smoker... How to calculate build tutorial...
					

>  Reverse Flow Smoker... How to calculate build tutorial... By DaveOmak   This is a tutorial and you will need a calculator and paper to note desired dimensions... This tutorial has been proven to make an excellent operating Reverse Flow smoker...  Here's to "Alien BBQ" and the folks that first...




					www.smokingmeatforums.com
				




I haven’t compared calculations to the Feldon. I used the tutorial here. I used 5” OD w/ 1/8” wall for my smoke stack. I do notice you have a sharp 90deg. I mitered mine 22.5deg to have a smoother transition to vertical.

also, are you using inside diameters in your calculations? Maybe I was wrong about your stack, could be the contrast in size to the CC & FB

the flow area under the reverse flow plate and the 180deg u-turn area is also important.

Run through the tutorial using flow wetted dimensions and compare to your actual build.

Fixing anything will require a grinder, cutoff wheel, & a welder.


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## Blazing_D (May 27, 2020)

I recently pucrhased a 20x36" reverse flow smoker from Pits by JJ. I joined this forum because i am having a similar issue that you are. My smoker takes at least an hour to get up to 250 degrees and is burning a ton of charcoal/wood. I went through a 10lb bag of B&B lump charcoal and probably another 5lbs of apple wood. Once it is at 250 it will hold steady for hours with a split thrown in every now and then. 

Coming from a UDS and burned about a quarter of the wood i am going through now. 

Not sure if it is normal to need to burn 15lbs of charcoal/wood. Hope you have luck with yours in the future.


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## rhaugle (May 27, 2020)

Blazing_D said:


> I recently pucrhased a 20x36" reverse flow smoker from Pits by JJ. I joined this forum because i am having a similar issue that you are. My smoker takes at least an hour to get up to 250 degrees and is burning a ton of charcoal/wood. I went through a 10lb bag of B&B lump charcoal and probably another 5lbs of apple wood. Once it is at 250 it will hold steady for hours with a split thrown in every now and then.
> 
> Coming from a UDS and burned about a quarter of the wood i am going through now.
> 
> Not sure if it is normal to need to burn 15lbs of charcoal/wood. Hope you have luck with yours in the future.




Mine take a LONG time to heat also... And I have trouble getting it over 265 (wanted to burn it in real hot... Nope)... My fire box is pretty big, but still have issues getting it hot.


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## daveomak (May 27, 2020)

Put upper air inlets on the FB...  That will move the heat in the FB to the CC....


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## sacedbysapp (May 30, 2020)

You need DRY SEASONED wood to get it up to temp, I’ve learned that the hard way. Check craigslist market place and start splitting your own and letting it season. That think won’t get hot on just charcoal. It needs dry wood spilts.


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## Big Bad Wolf (Sep 18, 2022)

rhaugle said:


> Also, I have been running the firebox door wide open, and the stack wide open also.


Sounds as if you definitely have an air flow problem. Several things I noticed about your exhaust stack. It has a 90 degree bend out from the cook chamber and appears to be too long letting the exhaust air cool and reducing the flow. On your cooker you can use a 4" dia. exhaust with 38" length above the top of the cook chamber or a 6" dia. exhaust 17" above the cook chamber or 5" dia. exhaust x 24 - 25" above the cook chamber. Not sure what size exhaust you have on it now but a 5" dia. x 24 - 25" above the top of the cook chamber would probably work best. Also need to try and get rid of  the tight 90 degree elbow somehow. Maybe an exhaust plenum on  the end of the cook chamber. Do Not close your damper on your exhaust pipe if you have one on top of the pipe. You also probably don't have enough air inlet for your firebox. You need about 22 square inches of air inlet for your firebox. About 75 - 80% of your air inlet below the fire level and 20- 25% of your air inlet in line with the opening from your fire box to cook chamber.


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## JWFokker (Sep 20, 2022)

Use dry wood, a lot of it. It will get very hot. Too big and it'll take the finish off the firebox. Use hickory or oak. Charcoal (lump only) is used to start the fire and that's it. I only use charcoal in an offset if I'm trying to keep the temperature very low.


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## sacedbysapp (Dec 17, 2022)

Any update here?


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