Full Fire Pot

Your fire is going out. Probably an airflow issue.

check the fans, maybe they aren't working right.

Every time I look at the fan it is running. It does look as if the fire in the fire pot sometimes is a flame and sometimes is smoldering. When pot is smoldering there is a lot of smoke. I guess I could hook up some type of recorder to the fan and make sure it is not turning off.

thanks Brad

Just give a call to CS. They'll be able to drive to a solution with you.

Its not a malfunction, I am guessing you used something like 100% cherry or some other fruit wood. I have had the same thing when using a lot of Cherry.

Well some more info. I tried the pellets of unknown origin that were in the smoker when I got it. The fire in the pot would blaze with the flames 2-3” above the pot then 20-30 minutes later the pellets would be barely be glowing. It would cycle through this sequence over and over. I then tried two new small bags of Bbqrs Delight oak with the same results. So it really seems the controller is overreacting to temps. The fan would go from a, say, slow mid speed to full speed in the 20 minute cycle. Almost like not enough air flow and fire almost goes out and temp drops, controller starts dumping pellets in and turns fan up. Fire in pot large. Controller slows fan down slows pellet feed and fire almost goes out, temp cools and the cycle starts over. I checked the temp probe with a Fluke meter and the controller and Fluke are within reason of each other.
Say at 225* what does your fire look like? Is there flame or just smothering pellets?

I tested the pellets for moisture and found all three types were about 5%. Seems reasonable.

Does anyone know what the functions of the pots on the rear of the control board control? Maybe I can adjust the PID control loops.

SmokinOkie, I talked to Bill at CS and he said it was the pellets, which after trying three different types it is not.

Bryan Rabe, the first pellets are a oak base with cherry and hickory for taste.

Call Bill back.

You know everytime someone posts this same problem everyone acts like this is new or its the operators fault.

My expereance with the smoker is that there are probelms with them. I agree that some units do not expeareance the flame outs or big temp swings like I, and others, have expeareanced. But someone elses working unit does not help my cooks.

My guess is that you bought a problem unit from someone that was given the same run around I have been getting for the last two years. So after 2 or 3 years they gave up and sold it to the next guy.

Oh trust me I know there are problems... I basically got shoed away from this forum for correcting them.

Hey Broncosaurs!,

The only time I have a big blame, is when I'm starting the fire with a handful of pellets or raising the temps. My pot does just what you are describing at 225*...A pellet or two flaming low with a few embers of burnt pellets.

I have also noticed that when I'm using a mixture of Cherry(BBQ Delights) with some CS hickory pellets. My fire pot runs two thirds full, unlike when I use only CS hickory pellets, which will run just under a half pot.

I have also learned that if I'm gonna have my door opened to play with the meat, I'm better off to take the shelves out and close the door. The longer the door is opened the MORE pellets are dumped which in turn will cause more heat spikes. I'm learning to stabilize my heat by dumping some of it as It comes to temp...don't know, but it seems to keep it from over shooting as bad.

LOTS of things to learn about my new pit, but hey that's part of being a real pitmaster.

quote:

Originally posted by cal:

I have also learned that if I'm gonna have my door opened to play with the meat, I'm better off to take the shelves out and close the door. The longer the door is opened the MORE pellets are dumped which in turn will cause more heat spikes.

If I plan on having the door open for a while I lower the temp setting which keeps the unit from dumping a bunch of pellets. This has worked fine for me.

Ill throw in a maybe.

I dont have mine any more, but never had flame out issues that you describe.

I did have temp fluctuations.

I solved mine by putting 6 half fire bricks on the lower shelf spaced apart an inch or so for air flow.

Once I did this, the temp swings all but went away. Perhaps that will help out your flame out issues?

Which fire pot do you have? I believe they are rethinking the cast iron pot and looking at going back to the stainless steel one. The cast iron pots with the angle bottom don't allow enough air flow in the bottom and needs more flat area to allow the pellets to continue to burn.

I had the EXACT same problem when using some different pellets.... usually a 100% fruitwood.

Never had a problem since using CS pellets

I ran a test last night and recorded temps from just above the fire pot to give me what type of fire I have, at the controller temp probe and at vent outlet. I also recorded the voltage to the fan to give me fan speed. I will get the data out of the recorder tonight.
I still believe I need a little more air flow to keep the burn going better. I don’t think I need more pellets because the pot is slowly filling up with some unburnt pellets. The fan, at least mine, speed is controlled by a PWM (pulse width modulation) output going to the DC fan. By adding an electrolytic capacitor in the range of 5 MFD – 500 MFD cleans the PWM output to a cleaner DC which in turn will make the fan run cooler and a little faster. I might try this out tonight. I also have an extra 12v power supply I could adjust up to 16v which should speed up the fan some. I wish I could get info of what the trim pots adjust on the back of the controller board. We will figure it out. Even if I have to build a controller using a PLC.

Smokers Purgatory
“My guess is that you bought a problem unit from someone that was given the same run around I have been getting for the last two years.”
My guess is that you are correct.

Cal
If you do a long say 18 hours cook will the fire pot over flow? I emptied mine at 8 hours and it was ¾ full after the next 8 hours.

Team Bucher BBQ
I have the SS pot.

Coach
I have tried 3 brands of wood. The last experiment was new bags of oak from BBQ delight. All with pot buildup problems. I do not think this cooker should be this sensitive on what wood is being used as long as it is quality pellets. I will see if I can get some CS pellets and give a try.

quote:

Originally posted by Broncosaurs:
The fan, at least mine, speed is controlled by a PWM (pulse width modulation) output going to the DC fan. By adding an electrolytic capacitor in the range of 5 MFD – 500 MFD cleans the PWM output to a cleaner DC which in turn will make the fan run cooler and a little faster. I might try this out tonight. I also have an extra 12v power supply I could adjust up to 16v which should speed up the fan some. I wish I could get info of what the trim pots adjust on the back of the controller board. We will figure it out. Even if I have to build a controller using a PLC.

You sound like smart man, I listen long time.

I think cleaning up the power would help. But I also think there is something wrong in the algorithms to the programming. If the temp swings are not very big ... the pot does not sit as long before running the fan or running it faster.

Smokers Purgatory,
I haven’t thought much about the control algorithm but now you brought it up you got me thinking. Here we have two outputs, pellet feed and fan speed to control one PV (process variable) which is temp. Off the top of my head I think I would let the pellet feed be calculated by the temp error and the fan speed calculated off the pellet feed speed. The fan speed is set to give enough air to burn the pellets completely, not to control temp. The faster the pellet feed the faster the fan speed. This could be a fixed ratio, or proportional control of pellet feed speed to fan speed with a user selectable offset for fine tuning. The pellet feed adds fuel to the system as to produce more energy. So the pellet feed system is in a closed loop PID with the temp.

Some things make you say “hummm”

Hey Broncosaurs!,

Yeah, my last cook was a LONG one. I started the smoker at 8pm with a handful of pellets on 180* set cook time for 10hrs, which included time for warmup period. I put in 4 PBs a little after 9pm and my pot of pellets was at the bottom holes and just embers, smoker was at 186*. I checked temp at 10pm before going to bed, it was at 182*. The smoker was set for hold temp of 230* and when I checked next morning, it was at 230*, I opened smoker at around 10am to foil 3 of the PBs and then turned the smoker to 250*. The pot was just below the top air holes.

I removed 2 PBs at around 11;45am and relocated the other two, they were done around 12;30, the fire pot was still in the same place, I then put in 3 slabs of LB ribs and did a 4 hr cook at 250*, while raising the temp to 260* the last 45minutes of cook...once again the pot was just under the top air holes.

I shut off smoker and when checking after it was cool, I had about 1/2 pot of ashes.

My cook would have been 20.5 hrs!

Just a question. You said you are using Lumber Jack Premium Blend pellets. Those are not cooking pellets. That company does make BBQ food safe pellets but they are called BBQ pellets. The Lumber Jack Premium Blend pellets are hard wood and pine. Could be a problem here.

Larry they are the BBQ pellets. I should have been clearer. Link below:

http://www.qpellets.com/

Well I couldn’t find my box full of caps. I did find a 700MFD and installed it across the wires going to the fan. With the cap installed, my guess the fan was running twice as fast at the slower speeds. Ran the smoker for 3 hours. Temp swings were very pronounced. With the fire pot almost out of fuel to a flaming torch as the controller added more pellets because of almost out and temps cooled off. Good news, no pellet buildup! Bad news, temp swings were worse. I need to find the box of caps so I can find a fan speed in-between. More air so I get a better burn and not get pellet build up. Not so much air as to burn to fast so not to run out of fuel. Maybe try it tonight.

Brad

Was having a similar problem. Resolved it by heating the unit and then dropping the temperature back to smoke.

Update, I found a box of caps. Went thru some hooking to fan and settled on a 100MFD. This gave about ¼ more fan speed when on lower speed. Ran at 225* for 5 hours. Temp swings to a minimum. High and low about +-10*. Opened door to upset temp to check for temp swing. Temp went down to 215, overshot to 235* then stabilized right on temp. Almost no buildup of pellets. Maybe ¾”-1” on bottom of pot. Poured out pot and pellets were 95% burned. Looks as if this might be the correct direction to go. I will run some other temps in the next few days to confirm this will work.

Using the 100MFD cap across the fan wires, over the weekend I started the smoker at 170* with nothing in it and let the smoker run for 7 hours. Turned off smoker and emptied pot out, fire pot was about 1/3 full and most all contents were ash. No un-burnt pellets except for what was on top burning. I then cooked 8 racks of baby backs, 2 hours at 200, 2 hours, about, at 275*. The smoker ran flawlessly. Temp swings were nonexistent. Fire pot had very little buildup. Every time I took a quick peek at the pot there was a little flame with glowing pellets. I do believe just like it is suppose to be.

1) Too little air flow, the fire pot will fill up with un-burnt pellets. Temp swings are from fire almost going out, drop of temp, the controller increasing fan and pellet feed, large fire, over shoot, etc.

2) Too much air, burn pellets to fast in pot. Fire almost goes out until controller adds pellets fast, too many, over shoot, etc.

3) Just the right amount of air. Not to much, not to little. Just right. Pellets burn completely. Enough pellets are added. Very little build up in pot. Temp is very constant.

Ate the best ribs I have ever done (and I have done a lot). I think I will go take a nap in baby bears bed.

I would like to be able to fine tune the air flow. If the fan gets a little old and slows down or different brands or types of wood burn a little different, being able to make small adjustments t the air flow would be a tremendous help. I could turn it down for the hot burning oak or up for the colder burning apple. I thing I am going to look down one of two roads.

Using an equipment cooling fan, axial flow fan, think a computer fan, that is on my smoker has two problems I see. One, is they do not like to push against anything; they don’t like to build pressure. Any type of restrictions will change the air flow drastically. Two, any small speed change at slower RPM will again change air flow drastically. I could use caps as above but I don’t know of any, say 10-700 MFD variable capacitors. So a power supply that the voltage could be varied will likely work. I do have a 12v supply that can be adjusted from 10-16v. I could replace the voltage adjust pot in the supply with an external pot installed on control box. This would be an easy solution.

The other road would be using a blower type fan, centrifugal blower. Something like McMaster Carr 8677K31 or a blower form TheBBQGuru.com. The idea would be to let these blowers run at a faster speed where they are more efficient. Then using an adjustable orifice to make the fine air flow adjustments. The controller will still have control of the fan. I do think this would be the most stable way. In the next few weeks I think Ill try the blower idea. I will let you know how it goes.

Brad

Are you sure you dont want to call Cookshack and wait for them to drive a solution to you?

Let us know how it goes Brad and Im not sure how, but I would volenteer to help with what ever I can.

Did a higher temp smoke at 300* with the 100MFD across the fan and the smoker did great. Good fire in pot, good temp control etc.