Reverse flow FLOP!!!

Discussion in 'Reverse Flow' started by uga fan, Aug 24, 2012.

  1. uga fan

    uga fan Smoke Blower

    Earlier this week I purchased a reverse flow cooker.. I drove 4 hours to get it but the price was right!!! When I got it home and attempted seasoning it, I had trouble getting the temp up.. Nothing I did with the dampers and/or exhausts could gt the temp over about 170.. To verify the reading was accurate, I filled a bowl with water and placed a thermometer in it.. It maxed out at about 140. I next placed a small household fan at the damper to the firebox, turbo charged it!!! I was finally able to get the water temp up to 162, still not hot enough to cook on!! Does anyone have any suggestions?? This is my first experience with a reverse flow cooker.. I have identified several design flaws that may be contributing but if I have a "bon fire" roaring in the firebox, surely the temp should be above 160!! The smoker can be seen at www.custompits.com. I bought the A1 model. Thanks for any suggestions!!!
     
  2. timleo

    timleo Smoke Blower

    Wow, that feels like a bit of a disappointment.  How big of a fire is in the firebox?
     
     
  3. uga fan

    uga fan Smoke Blower

    I had three split red oak logs fully involved!! Blistered the paint on top of the firebox because the flames where hitting the top and then spreading.. It looked like a small bon fire inside there!!
     
  4. uga fan

    uga fan Smoke Blower

    One thing that I have noticed, the vent from firebox to smoker isn't located at the top of the fire box!! It's approximately three inches down.. To be optimally efficient I think it should be at the top where the hottest heat is. Also, the shelf for the logs seems awful high.. It's about 12 inches of the bottom of the firebox bottom.. I was debating on lowering the shelf and see if that helps.. When I pile wood in, the stack is higher than the vent!! Just hate spending $$ on something and start cutting/grinding/welding..
     
  5. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    UGA Fan, afternoon.... I looked at the smoker A1..... There are a few details I do not understand..... I will reserve comment until you have looked at the calculator below.....  measured your new smoker and compared it to what is suggested in the calculator....  and maybe even called the manufacturer and asked what to do to correct the temp problem....   

    Did they give you a manual describing how to operate the smoker ???     Dave

    http://www.feldoncentral.com/bbqcalculator.html
     
  6. bruno994

    bruno994 Master of the Pit

    From studying the website and pics, there are a few design flaws.  The heat and smoke need a clear pathway into the chamber.  I am curious if the opening at the end of the RF plate is the same or larger than the opening from firebox to chamber.  This could be causing a chokedown of heat ab dair flow as well.  As far as the log rack, yes, depending on size of your firebox, the rack shouldn't be any higher than 3 to 4" off the floor, just enough for an ash pan to fit under it or enough room to clean out with an ash shovel during long smokes.  As Dave suggested, call the manufacture, maybe there is a secret to dialing in their rigs.  Post some interior pics of the pit when you get a chance, from the website, the firebox does appear to be mounted way too high to the main chamber.  Looks like they did this to accomodate the pit sitting in reverse fashion on the trailer.  Typically, the firebox would be hanging off the back of the trailer or tied into the trailer at the back, sitting lower than the pit by a good 6"-12".  Other than your heating issues, it is a good looking pit, I'd be proud of it.  I would also be concerned about the propane tank holder being on the backside of the main chamber.  Might be bad...just a thought.
     
    Last edited: Aug 24, 2012
  7. piaconis

    piaconis Smoking Fanatic OTBS Member

    I agree with Dave.  Run it through the calculator.  Sure looks like there are some issues from the pictures, but sometimes pics are deceiving.  Numbers don't lie.

    Sorry to hear you're having a bad experience.
     
  8. uga fan

    uga fan Smoke Blower

    Thanks Dave!! That showed me a lot!!! Basically my firebox is 63% to small!!! So now please comment what u saw on the smoker please!!
     
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    UGA..... What you are describing is not a reverse flow smoker.......  have you looked at a reverse flow smoker to see how they are built ??

    Here is the design schematic......   Dave

    [​IMG]
     
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  10. uga fan

    uga fan Smoke Blower

    I have talked with the manufacturer, basically a small town welding shop!! They told me that no one has had any problems yet and we went thru the steps with the dampers and the chimneys.. I was doing everything like he suggested.. I have another question, the plate that runs underneath the cooking grates is slanted going downhill.. I am sure this was done to increase pressure as the heat passes through. But my common sense tells me that heat rises!! If the channel it passes through slopes down, the hotter air is staying high as the cooler air enters the cooking chamber.. Am I making sense??
     
  11. bruno994

    bruno994 Master of the Pit

    UGA, yes, heat does rise, but it will also be looking for an exhaust.  My question in my earlier post was a critical factor in RF's, is the opening at the end of the plate at least as big if not bigger in surface area as the opening from the firebox to the chamber?  If not, and the slope of the plate, wil  be choking your heat flow off and you will never draft properly to achieve proper temps. Also, how did you have your exhaust set while doing the test run?  Wide open or closed off, or somewhere in between.  As far as the slope of the plate, it shouldn't slope that much, just enough to move the fat and drippings to the drain. 
     
    ben bot likes this.
  12. uga fan

    uga fan Smoke Blower

    Bruno, the opening at the end is substantially bigger than the opening between the fire bos and the cook chamber.. I will try and get some exact measurements shortly tho!! As far as the exhausts, I have two one on each end of the cooking chamber. When starting the fire, I opened both fully. After the fire started burning fully, I closed the one at the far end of the firebox and left the one nearest the firebox fully opened. I played with that setting from halfway to full, neither bearing favorable results!! And I had to continually open the firebox door in order to rekindle the fire.
     
  13. bruno994

    bruno994 Master of the Pit

    As long as the opening is larger at the end of the plate than at the firebox, that shouldn't be a problem there.  With you saying that you had to keep opening the firebox door to keep the fire going, you aren't getting enough oxygen to the fire.  Make sure both dampers on the firebox are fully open and even crack the door a bit on the firebox, when I need extra temp, I just slightly crack my door and it starts gradually rising.  As far as the exhaust, try leaving both fully open.  The more draft, the higher the temp will get.  On my RF, it doesn't take much of an adjustment on the exhaust and my temps will start rising pretty quick.  
     
  14. Wow, they put the firebox on the tongue of the trailer?
     
  15. bruno994

    bruno994 Master of the Pit

    Thats what I was thinking, odd design to say the least.  The A2 on theri website, is an odd duck also.  Personally, I would request my money back and call Lang. 
     
    Last edited: Aug 24, 2012
  16. uga fan

    uga fan Smoke Blower

    I don't think a refund is gonna be a viable option.. 1 it's about an 8 hour round trip drive 2 I doubt they would do it!! The smoker is at best fixable and I'm sure some how I can make it work!! Bruno, the vent feeds into the cooking body thru the vent. Inside the cooking chamber there is a solid plate front to back creating the reverse flow. There is no flue so to speak, so the opening is roughly 25 inches wide and about 18 inches tall(the bottom half of the body)..
     
  17. scarbelly

    scarbelly Smoking Guru OTBS Member

    How did you pay for it ? If by credit card you have some negotiating power. If by check and they have not cashed it yet you can always put a stop on it  
     
  18. uga fan

    uga fan Smoke Blower

    Cash....
     
  19. bruno994

    bruno994 Master of the Pit

    I do have another question, why is there a stack at the opposite end of the firebox and also one at the firebox?  If the stack opposite the firebox is open, that would create a major loss of heat.  You should need only the one on the firebox end, and of course the ones for your charcoal grill.   It is, as any smoker or pit, fixable, but if the firebox is 63% too small, you will probably have to run it wide open (dampers, intakes and door slightly cracked on the firebox) to get 225.  I'm just having a hard time picturing some of the guts to the pit without pics (it is Friday after all...LOL).  If you can, post some pics this weekend, but of course if you already have a plan, shoot that at us too.  I'm sure Dave will be back here to correct any of our mistakes.  Good luck to you.  It really is a good looking rig, congrats on the purchase, now let's get her cooking!
     
    Last edited: Aug 24, 2012
  20. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    UGA Fan,  Take all the measurements that are needed for the calculator and we will figure out what you need.. if anything at all....   

    The stack closest to the firebox should be wide open at all times.... If you are not getting enough heat to keep the smoker up to 275, there are some design flaws that can be corrected.....  Like others have said, pictures of all the inside would help... use something for reference in the pics so it is easier to decipher...    Post the measurements and pics.....    Dave
     

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