Author Topic: Another Temperature Test  (Read 282 times)

Offline Habanero Smoker

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Another Temperature Test
« on: August 12, 2020, 01:29:27 PM »
Since I was doing a White Bread Test, I decided to also do a temperature test. This was my forth temperature test, I didn’t write up the third test because there were too many variables that could have skewed the results. I used a similar method of another temperature test Temperature Test Pt. 2; using my ThermoWorks Signal, four probes, and two racks – positioned at the 1st and 3rd rails. The four probes used were two ambient probes, and two food probes. Two probes on each tray, one front center about 2-inches from the door, the other back center about 2-inches from the back wall. In my other tests I placed one ambient and one food probe on each tray – using the ambient probes in the rear of the tray. During this current test I used both ambient probes on the bottom tray, and the two food probes on the top tray.

The test was started at 11AM, ambient temperature 76°F, calm conditions, and in the shade. It ended at 2:30PM, ambient temperature 86°F, in the sun. The cabinet temperature was set at 251°F, the bisquette burners turned on, and water in both bowls. As with my previous tests, during the preheat the Signal probes would record temperatures as high as 40°F higher than what was being shown on the Bradley display. Again, when the Bradley got within 10°F of the set temperature, it appeared to be auto tuning.

It took about 20 minutes for the Bradley display to reach 255°F. I let it run for about another 30 minutes to make sure the temperature was stable and displaying 251°F +/- 3°F. Though I’m stating +/- 3°F, it was generally +/- 2°F, with an occasional 3°F.  During this time the Signal was averaging temperatures on Bottom Rack Back (BB) 281°F; and Bottom Rack Front (BF) 279°F - Top Rack Back (TB) 273°F; Top Rack Front (TF) 270°F; +/- 3°F (any fluctuation in temperature corresponded with what the Bradley was displaying). This test showed that the temperatures for the front and back on each tray level were pretty even. This is way different from the results I got during my first test. It could be that I used the ambient probes, and the food probes on the same trays.

At PM 11:53AM I loaded the bread for the bread test. The bread took about 2 – 3 minutes to place on the trays. During that time the cabinet temperature dropped to 119°F, by the Bradley display. I should make you aware that when the door is opened all electronics shutoff, then resume when the door is closed. The Bradley recovered within 8 minutes, but over shot by 5°F. For the next 35 minutes the Bradley and Signal was reporting close to the same temperatures. While the Bradley was reporting temperatures of 249°F to 253°F. The Signal was displaying average temperatures of; Bottom Rack Back (BB) 261°F; and Bottom Rack Front (BF) 254°F - Top Rack Back (TB) 256°F; Top Rack Front (TF) 249°F; +/- 3°F (same fluctuation as the Bradley was displaying). I’m not sure why this occurred. When the sun started to shine of the Bradley I again started seeing the 20 degree or more disparity.

After the sun hit the cabinet and the ambient temperature rose the Signal was displaying average temperatures of;  Bottom Rack Back (BB) 276°F; and Bottom Rack Front (BF) 272°F - Top Rack Back (TB) 273°F; Top Rack Front (TF) 270°F; +/- 3°F (same fluctuation as the Bradley was displaying). While the Bradley was displaying a temperature 256°F. In previous test the Bradley adjusted to the external heat of the sun and keep the cabinet at 251°F by its display, this time it couldn’t. I ran it an additional 30 minutes but had to shut it down due to a pending T-storm.

This is the last temperature test I will do until I use this smoker for a while more. I’m not sure if the PID is continuing to learn, so I will hold off for a while before conduction another test.



     I
         don't
                   inhale.
  ::)

Offline gizy-CA

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Re: Another Temperature Test
« Reply #1 on: August 17, 2020, 10:27:14 AM »
Yesterday I did my P10 ....temp test.I set smoker (sensor) temp  at 176 F. I let it run for half an hr or so....Then I drop in thru the vent my PID  probe and after 5 minutes PID shows 188 -189 F ..inside the chamber....and the 2 probes inside ... that comes with smoker shows the same +/- 1-2 degrees  same like PID .So it shows that there is a 12-13 degrees different between Bradley smoker sensor and 2 probes and PID.
I wouldn't worry much if it was a 2 degree different but over 12 degree it is a BIG problem. I was wondering if there is a any way to fix it or adjust ?

Offline Habanero Smoker

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Re: Another Temperature Test
« Reply #2 on: August 17, 2020, 02:30:06 PM »
I'm glad you perfumed a temperature test.

 I'm finding that the rate of difference is exponential. The higher the set temperature the greater the difference in the reading. When I did a test at 180 I was getting readings close to yours, it was around 15°F difference. At 200°F the reading difference was about 20°F. At 251°F, the difference is generally 25 to 30 degrees difference. Hopefully Bradley will come up with a firmware fix. I'm going to send them an email to inform them of the problem I'm having, but I want to do a few more cooks. Also my P10 is not displaying the firmware version when it is being powered on.

So at this time:
If I want to smoke/cook at 200°F, I set the Bradley at 180°F;
If I want to smoke/cook at 225°F, I set the Bradley at 200°F;
If I want to smoke/cook at 250°F, I set the Bradley at 230°F; (I need to double check this to see if the best setting is 230° or 235°)

If you use the above adjustments that will get you in the ballpark. Even a 5 to 10 degree difference after you make the adjustments in temperature settings is still good for most meats. One important thing is that once the Bradley obtains its temperature, it holds it within +/-3°F.
« Last Edit: August 18, 2020, 02:13:07 AM by Habanero Smoker »


     I
         don't
                   inhale.
  ::)