I just finished doing the heat test that Bearcarver suggested. I set the MES for 230, checked my Mavercks in ice water against my Thermapen.
As you see there are + - 2 degree from my Thermapen. Set the probes in the smoker as Bearcarver suggested.
The local weather was 54 and very windy. Set the MES to 230 with the vent opened all the way and started taking readings. While the MES was heating up the difference between the probes was 20+ degrees difference. After the unit hit temperature I waited 15 minutes for the unit to stabilize. The probes read
Left side 222, Right side 228 and the MES temp gauge was 235. I am not concerned about the big difference in temps while starting up as I always wait for my smokers to stabilize at least an hour before in put my food in.
Waited 15 min. for the next reading.
Left probe 219 right probe 225 MES probe 238, MES meat probe 235
After another 15 min.
Left probe 225 right probe 232 MES probe 244 MES meat probe 239
Another 15 gone by
Left probe 216 right probe 221 MES probe 231 MES meat probe 226
Left probe 226 right probe 232 MES probe 242 MES meat probe 325
Last 15 test
Left probe 218 right probe 223 MES probe 237 MES meat probe 229
As you can see the biggest delta between the probes was 8 degrees. At any given time the biggest difference I saw was 9 degrees for a minute or two, that was in between the 15 minute duration. I can live with this difference in temp as my Big Green Eggs have a hot spot in the back while using my plate setter. I would strongly suggest not going by the MES units temperature probe as there is a big discrepancy between my calibrated probes and the MES probe. The MES meat probe was attached to the side wall for all the above readings.
The only reason I can think of is Bearcarvers unit may have had a 800 watt heating coil while this model has a 1200 watt coil. I would think the 800 watt coil would be on longer to bring the unit back to the set temperature causing the one side to heat up more. But seeing as I'm not a scientist and I'm only a grease and oil man, what do I know.