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brute_strength

Used Vision Owner, Struggling w/ Temps

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Hello, all!

 

So last time I posted, I was trying to decide between an Akorn and a Kamander, but I was fortunate enough to get a gently used Vision Classic B series instead (the one sold at Costco once upon a time).  It's an excellent grill, and I've had some successful high-temp cooks as I'm learning the ins and outs of Kamado cooking.  My frustration, though, is coming from trying to maintain temps for a smoke.

 

I have been scouring this forum for hints and tips, but so far nothing has worked.  There aren't any discernible leaks that I can see.  When I shut the top and bottom vents, the fire snuffs out pretty fast, and I don't see smoke escaping from anywhere.  Could there be someplace air is sneaking in, but not necessarily out?

 

I've spent the last few days frustratingly trying to get it to maintain temp.  Yesterday I tried the method described by Nunyabiz in an old, related thread (leaving bottom vent wide open, and controlling temp from the top) and that didn't seem to work.  Today I lit my lump (couple of hickory chunks buried just so it's a true practice) and once I had some flames licking, I put in my DIY crossmember and diffuser.  I installed the grates, closed the lid (grill probe inside) and left both vents wide open until I hit 175 (took 2 or 3 minutes) at which point I closed the vents down to about 2 on the bottom and .75 on top.  The temperature started to drop pretty quickly and I was at 164 before I adjusted the top vent to 1.  It was still struggling to get back to 175 after about 10 minutes, so I opened up to 1.5 on top.  It's been close to 90 minutes and the temp just keeps rising, albeit slowly.  I'm at about 324 and still gradually climbing.  I was hoping to hit a "ceiling" temperature that these settings would maintain and give me an idea of where to go from here, but so far there does not seem to be an end in sight.

 

I saw in another thread that a user had success removing the shock-absorbing tower from the front of his grill, but am hesitant to try this.  I really, REALLY want to learn this grill and start doing some serious slowish cooks (brisket, pork butt, etc) but I am feeling a bit discouraged.  As I understood it, the previous owner used this exclusively for burger/steak type cooks.  No low and slow.

 

Using Royal Oak lump from Walmart, if it matters.

 

Thanks so much, guys.  Just writing it all out has made me feel a bit better, lol...  Let me know if more info is needed.

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How much lump are you lighting?  And what is actually your target temp?  175* is far too low even for "low and slow" if that is what you were aiming for and would be difficult to maintain for sure.  You want to try to avoid getting a fire too big in the beginning, try lighting a single spot in the center and closing down the vents in half setting increments until you get to your target, you want to start early and make very small adjustments as you go.  Try for a target of 250-275.  I've found it very common that it can be rolling along and all of a sudden it can jump 20 or 30 degrees as new fuel catches, but within 20 minutes or so it will level back out, try to resist the urge to constantly fiddle with vents if you can.  You are really just looking to smoke in a range of temps.  325* is really not too high for something like a pork shoulder it will still turn out very good.

 

 

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I second the suggestion of lighting one spot. Are you using a stone? Is it on the main grate or below? Do you get a seal all away around the lid and the bottom felt? There might be a gap in the back, just a thought. You could also try lighting one spot and set your top and bottom vents to 1 or half and just let it ride to see what that temp is after an hour or more. This would give you an idea on what temp to expect when at vents are at 1. Keep trying and soon you will get the hang of it. 

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Open the bottom vent, screen guard and everything.Open the top vent all the way. Light the coal in a couple places, or pour in a chimney of lit coal on top of a pile of unlit coal. Leave the lid open until everything is burning .  It should get screaming hot. Maybe even remove the top vent entirely. Never had to do that, though.

Low and slow, I usually light a tumbleweed or two, follow the above procedure, placing the diffuser in position after the fire is started, be it a small flame, or partial lit chimney of coal. Around 200 or a little earlier, I dial back the two vents, bottom about a quarter open, top on 1.5 -2.. It may drop a little and then come back up. Adjust as needed.

Low and slow, It can take a while to get up to temp, so allow for that.

Maintaining low and slow, usually top vent barely open, almost closed. Bottom vent usually closed down to where only about 4 of the holes in the perforated guard are visible. 

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Hello, all.  Thank you very much for the suggestions.  I apologize if I gave the impression that I was aiming for 175.  That was the temp where I dialed back my vents and started trying to settle in somewhere between 225 and 250.  With no adjustments, the grill continued to crawl for another 30-40 minutes.  It was in the 380s before I finally decided to shut it down.  I had been filling the firebox to just under the line of holes (per the instructions, I think) and just lighting things up in the very middle with a torch (or some alcohol-y cotton balls if I was feeling easy about time).  Once I had some licking flames, I installed the pizza stone I'm using as a deflector (in a DIY crossmember beneath the first grate) and both grates.  My probe was sitting on the second grate, near the middle.

 

Despite the fact that there aren't any discernible leaks when I close it up at the end of a cook, there MUST be extra oxygen getting in from somewhere. I noticed that there is considerable play between the bottom vent sliders when they are not closed.  I'm going to go ahead and try the ball-bearing fix and see if that solves my problem.  I have a tube of Permatex on standby in case problems persist to try achieving a better seal over the stock gasket.  Beyond that, I'm out of ideas.

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A small update.  I epoxy'ed the bearings to the sliding door.  It fits EXTREMELY tight now, lol...  I'm doing a test burn right now.  Even with the top and bottom vents both at 1, we are hovering around 300* (just tipped 309, to be exact).  Is that kind of high?  Or is it just me?  Airflow does seem a bit more regulated, but I feel like temps are still too inconsistent and high.  Should I try resealing the whole housing using the Permatex?

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Your problem is NOT air leaks!  Your problem is adjusting your vents and chasing temps.

 

 

I cooked for almost a year with almost none of the original gaskets before replacing them. Even if you had leaks you would be able to control it with the vents. Set the top vent just barely open...a little less than a quarter inch. Set the bottom vent at three quarters of an inch and let it ride for an hour or so. Don't touch it. See where it settles in at and then make a small adjustment to the top vent only. like an eighth of an inch at a time. 

 

 

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@brute_strength My dad has the same grill and it is extremely sensitive and efficient. Paired with some dry charcoal, I can understand your troubles. As landscaper mentioned, I believe your difficulty comes from controlling your vents and not air leaks. If you can snuff out your fire easily, you don't have an air leak problem.

 

It's amazing how sensitive these grills are so don't be afraid to slightly, and I mean slightly, have the vents open (top and bottom) or tap them to adjust. 

 

I would also recommend limiting the amount of charcoal you use and consider using chicken for your test cooks as they don't take long and is not very expensive if you mess it up. As you get better with temp control add more charcoal and go for longer cooks.

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Just getting back to these replies.  Thank you for the tip, @landscaper .  I already have a pork butt on (.99/lb!) but my next dry run I'll try the settings you mentioned and see where I end up after an hour.  Right now, my bottom vent is at 1 and my top is also at 1.  My top settings have varied from 1 to 1.5.  Been trying to stay in the 275-300 range, but she seems to not be happy unless she's burning north of that, 310 to 315.  Adjustments (that I thought were minor) sent me down into the low 260s.  I guess @Akorn Rand is right in that these grills are very sensitive.

 

I have read time and again that kamados in general are really good at maintaining temps for long periods, with many claiming to cook overnight without worry.  I would certainly NOT trust my grill that much right now, lol.   I'm anxious to learn this grill and compare its results to my other cooker (a pellet rig), I guess I just didn't expect to have such a hard time with the learning curve. 

 

Thanks again for the help.  I'll keep at it.

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Another test burn, another frustrating chapter.  I tried closing the top and bottom as directed by @landscaper once I was up to about 205.  Was aiming to settle between 275 and 300.  The temp in my grill started to drop.  It fell to about 195.  I gave it another 20 minutes or so and it crawled up to 204.  Frustrated, I bumped the top up to 1.5.  Temp rose up to about 289 and stayed there for close to an hour.  I left it alone for another hour and it had climbed up to 335.  This time I left the top alone and closed the bottom to about a half inch or a little less.  Over the hour that followed, temps dropped back into my target range and then further into the low 270s.  I decided to leave it alone for another 30 minutes.  When I checked again, I was heading into the 230s.  At this point I was done being disappointed for the day, and decided to open her up and get a look at the coals.

 

The coals were not really burning much at that point, which probably accounted for temp drop.  There was still plenty of fuel, but for whatever reason it hadn't caught to keep things going.  I am open to the possibility that ash/small lump could have clogged airflow somehow, but I have already cleaned the thing out several times since I got it.  I'm still on the same 30lb bag of Royal Oak lump, about halfway through, and my understanding is that efficiency + lump = less ash.  So I don't know.

 

Hoping someone has more light to shed.  Otherwise I guess I'll just keep making progress reports, ha...

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This all sounds very much like an early thread I posted. TLDR nothing worked until I got all the crumbs and tiny cloggy bits out of the firebox so I could lay a proper fire with wood chunks/big charcoal pieces on the bottom.

 

If your RO from Walmart is nothing but pebbles, stop buying it there. I had the same problem with big RO bags from Home Depot. Something in how they transport or manhandle their charcoal out of warehouses and trucks just pulverizes it and you'll never get a good bag. I switched to RO small green bags from Menards and stopped having problems, then I picked up a couple bags of Big Block at the last KJ Roadshow at Costco and never looked back.

 

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If your problem is lots of gravel-sized charcoal the only thing a wider-spaced grate will do is let more of it fall into the ash pan, which I guess partially solves the problem but is probably not a definitive solution. Here's what I would do:

 

  1. Stir up the leftover charcoal a lot to knock the ash and gravel through the grate.
  2. Push what's left out to the sides of the firebox. (If there are some big pieces reserve them for the next step.)
  3. Place some fist-sized wood chunks and big pieces of charcoal (probably from a new bag that's not smashed to bits) in the center, leaving a space in the middle and with breathing room around the chunks/pieces.
  4. Lay on more charcoal on top of this structure. You can get a little carefree here but leave the central pocket so you can see all the way down to the grate. Block it off with a can if you want (as long as you remember to pull it out).

 

Now light it as normal. For me this means putting one 91% alcohol-soaked cotton ball into the well in the middle, lighting it, laying a couple of this pieces of charcoal over the well, and shutting the lid after a couple of minutes. However I use an Akorn and those things heat up crazy fast, so your method may differ. The important thing is to have open air channels from the lighting area through the ashpan to the lower intake so you can maintain oxygen flow, even the tiny amount a kamado needs.

 

After the cook or test burn, stir up the remains like before and repeat. Clean out the ashes when you need to.

 

Once you get this working you can proceed to learn more about how your kamado works.

 

The only other thing I'd mention for airflow is that I like to keep the open surface area at the top more open than the bottom intake to maintain a vacuum effect in the cook chamber. I find this important to prevent fire snuffing and maintaining clean smoke.

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Thanks, @Ogopogo.  I'll give it at try.  Maybe I'll handpick the pieces for my next test, see if it makes a difference.  I'll also see about keeping the bottom vent fairly tight and try having the top vent a bit more open to compensate.  Maybe along with possible clogs my vents just aren't fostering enough of a vacuum while I'm trying to maintain lower temps.

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Don't worry too much about vacuums or positive pressure or whatever; first just hold a smoking temp without the fire going out for many hours. The rest should follow naturally. It took me a week to be able to do this consistently because of the gravel-sized charcoal problem, which is why I recognized your issue.

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