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**Pellet cookers** - YS480, YS640
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**Pellet Cooker Warranty**
August 31st, 2020, 1:14 pm
* Abilene ** Abilene *
  • Joined: August 31st, 2020, 9:52 am
  • Posts: 2

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.

• 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

• 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)

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

- 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.


September 23rd, 2020, 10:23 am
* Abilene ** Abilene *
  • Joined: August 31st, 2020, 9:52 am
  • Posts: 2

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?

September 29th, 2020, 5:13 pm
* Abilene ** Abilene *
  • Joined: May 5th, 2020, 10:50 am
  • Posts: 1

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?

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