Yoder Smokers Community Forum

I recently purchased a Yoder YS640s and have been having issues with uneven temperature from left (firebox side) to right (chimney stack side). These issues were present both times I have used the smoker which were for cooking brisket on two different occasions. A right side ambient temperature probe consistently read 35-70°F degrees hotter than a left side ambient temperature probe. With the brisket inside the smoker, it was generally 40°F hotter with the smoker set to 225°F, 50°F hotter with the smoker set to 250°F, and 70°F hotter with the smoker set to 300°F.

Equipment
• Yoder YS640s
- Standard heat diffuser (1 piece)
- Full sized second level cooking shelf
- Standard bottom cooking grates
• Fireboard FBX2 6 channel thermometer
- Ambient probes (100k thermistor) that came with the Fireboard kit
- Meat probe (100k thermistor) that came with the Fireboard kit

Setup
• Verified the smoker was level by placing a level on the cooking grate
• The heat diffuser was bare and was not wrapped in foil
• Damper was pushed in 5” from the chimney stack end for even temperature across the grates (per user manual)
• No water pan was used
• Nothing was in the smoker except the brisket, the meat temperature probe, and the two ambient temperature probes
• Left ambient temperature probe
- 4.5” from the left side wall (firebox wall)
- 1” above the cooking grate
- 2” from the brisket
• Right ambient temperature probe
- 4.5” from the right side wall (chimney stack wall)
- 1” above the cooking grate
- 2” from the brisket
• Meat
- 12 lbs trimmed brisket
- Oriented left to right with the flat closest to the firebox and the point closest to the chimney stack
- Centered exactly in between the two ambient temperature probes
- Placed on the top rack (for this cook)
- Placed on the bottom rack (during my previous cook with the same uneven temperature issues)

Result
Yoder YS640s w Brisket On the Grate
Set Temp Smoker Temp Left Right Difference
225 221 199 240 40
250 253 217 267 50
300 305 277 349 71

NOTE:
- Smoker temp is based on the reading from the YS640s built in thermostat for the smoker
- Left & right temp is based on the Fireboard FBX2 ambient probes

During my cook, I was attempting to even out the heat distribution by adjusting the damper. I started out with the damper pushed in 5” from the chimney stack end for even temperature across the grates (per user manual). This resulted in the right side being 40°F hotter. After 2 hours, I pushed the damper in another 3” and waited another hour. The right side was still 40°F hotter. I made various other adjustments to the damper, including all the way in and all the way out. Each time I adjusted the damper, I waited at least an hour for the temperature settle and I did not notice a significant difference. Each time the right side was significantly hotter. At no point was the temperature difference less than 35°F.

You can see some of the temperatures I had in the chart above. One thing to note is that I am new to smoking meat. I read as much as I could prior to smoking the brisket. I ended up following AmazingRibs.com’s brisket recipe. I started my cook at 225°F. I wrapped the brisket in pink butchers paper and put it back in the identical position on the smoker when it hit an internal temperature of 160°F. A few hours later I realized the smoke was going slower than I had anticipated. I decided to raise the temperature to 250°F about 12 hours into the cook. I then raised it to 300°F about 15 hours into the cook. I know you are not supposed to mess with the temperature like that but eating dinner many hours later than anticipated was not an option I wanted to entertain (angry wife!). However, regardless of the smoker temperature, the right side was always 35-70°F hotter than the left side.

I called Yoder’s support line during the cook and asked them how to fix the temperature difference. I was told by the employee that the temperature difference I was seeing between the left side and right side was not irregular due to the ambient temperature probes being placed so close to the side walls. He said when they calibrate the YS640, they calibrate it with temperature probes placed 11” and 22” from the firebox wall. I was told to simply avoid the far right side of the YS640 (chimney stack side). I also asked if I could even it out by putting a water pan on the right side. I was told water pans are not recommended with pellet grills as they are more for stick grills. He also said the steam could mess with the controller’s temperature readings.

Is this correct? Is it normal for me to see the right side (chimney stack side) being 35-70°F hotter than the left side (firebox side)? Is there nothing I can do to minimize the temperature difference?

Also, what is the best positioning for brisket placement on the YS640s specifically? Side to side (flat by the firebox and point by the chimney stack), front to back (point by the door, flat by the back or vise versa). Top rack vs bottom rack?

In the future, should I even bother with the variable displacement damper in the future?

I know this post was a bit lengthy, but I thought it would be beneficial to provide as much details as possible. Please also note that I am new to smoking meat and I am doing my best to learn. Any advice you can provide would be much appreciated as I plan on smoking many more meats (brisket, ribs, pork butt) in the future.

Cheers!

It's been a little over 3 weeks and I haven't received a single response. I'm thinking of reposting this question on a different forum. Does anyone have any suggestions on another BBQ forum that has an active community?

Hey there,

I bought a yoder smoker back in May and mine is having the exact same issue. Until now i have not found a solution. Customer service told me the exact same thing as they did to you. Even now i just did a brisket on Sunday 27th Sept and still have the same problem. At this point I've just learn to cook accordingly in my chamber but its annoying as my right side of the brisket gets cooked quicker then the left side. and sometimes like on sunday left my brisket one side a bit over cooked and the middle where the point and flat meets, was left slightly undercoked.

was wondering if you found a solution yet?

I don't suppose either of you have had any success getting help with this issue? I've had my YS640 for about a year-and-a-half, and have consistently had the same issue you described. I was doing some wings for the super bowl at 225, and the right side actually spiked to over 400 degrees. That's definitely extreme, because I normally see anywhere from 40 to 80 degree differences left to right, even with damper pushed in 5" per Yoders own instructions. One of the things these Yoders are touted for is their consistent temperature. If I had known I was going to have the same hotspot issues with a $2,000 smoker as I've had with the cheaper ones, I wouldn't have spent the money. It's certainly a well-built smoker, but to still have these kinds of variation issues is pretty frustrating for a high end piece of equipment.

I received my 640S a couple of weeks ago and am having the same problems. It is frustrating to set the temperature and not be able to trust that the temperature selected is accurate. I’ve been using pellet smokers for many years and have never had trouble with such uneven temperatures across the grate. Last week I cooked some ribs and had one rack very undercooked while the other was perfect. Both were cooked exactly the same way for the same time. Come on, Yoder! I’m not ready to give up on you, but why are we getting such uneven results?

I have had my YS640 since 2014, I have updated the controller to the new one once it was available. I ended up totally removing the whole damper assembly, as I always found it a pain to clean around the inside of the smoker and never found much change in temperature when trying to set it anyways. I can cook a brisket over night, I like to use the top shelf, and even though I only have the 2 door thermometers they end up staying at the same temperature. I do the same with ribs on the top shelf and they turn out great. I find that the top shelf is 20-30 degrees cooler then what the controller says, going off of what the door thermometers are reading, so I compensate a bit for that. I find it's alot of trial and error until you get a feel for your grill and dial it in.

I've had my Yoder YS640s for about a month now. When I first got it my temps were also 35-70'f when I placed the probes about 3 inches in from the left and right. Then I ran the official Yoder temp test and was getting up to 22'f difference between the two probes which were 11 inches apart in the middle third of the grill.

I contacted support and ran a couple of temp tests with them (Larry and Joey). I was convinced something wasn't right because I can hold a 15-20'f difference end to end on my 60" offset stick burner so surely the Yoder can do better. After reviewing a couple of tests, one with the variable damper all the way out and another with it 5" in, they realized something wasn't right with the temperature because the temp was rising according to the pit but not the probes and they came to the conclusion that it was possibly a bad thermocouple.

They overnighted the new thermocouple which was great! I've installed it and just finished running a temp test and it's FIXED !!! My probe temps placed according to the official Yoder temp test haven't gotten more than 4'f apart and I'm soooooo happy right now.

Thank you Yoder support!

I've been having the same problem. The right side is significantly hotter than the left. Normally, this is not a problem, though inconvenient. I am now cooking three racks of St. Louis style ribs, which fills up the top rack of the grill. Because of the temperature difference between the left and right side of the grill, the rack of ribs next to the smoke stack was ahead of the rack of ribs on the far left by 10 degrees within just the first hour. Like everyone else is mentioning, I set everything according to the instructions included with the grill. But, nothing seemed to work. I decided to experiment, and open the steel plate covering the fire box by about a half inch to even out the heat (considering the right was too hot and the left was too cool). That seemed to make a favorable difference. After a few more adjustments (moving the steel plate covering the firebox), I got the right and left sides of the smoker to be consistently within 5-10 degrees of each other. For my situation, sliding the steel plate covering the firebox to the right to create a 1 to 1.5 inch opening seems to have evened out the temperatures across the top rack of the grill. I used two separate external electronic temperature probes to verify this (in all, I am using 4 probes: 2 for the meat and two for the left and right temperature measurements). All considering, it took about an hour to get the temps to behave the way I wanted. I don't know if this is a factor, but the outside temp where I live right now is 32 degrees and I am not using a thermal blanket on my grill. As my reward for my accomplishment this morning, I am now going to have a cigar and enjoy the company of my dog on a nice walk in the crisp air and bright sunshine before I have to start spraying my ribs.