Guru Stoker temp test

[Jim Bloomfield]

I have been having a issue with BBQ Guru new style probes. They read up to 20 degrees to high when used in meat in the pit.
I have called the folks at BBQ Guru they sent new probes. I sent back my old ones which they tested and found good.
Tested outside the pit with boiling water/cold water they are within a few degrees.It is when they are in a pit that they run higher.
I did a test where I set up a pan with water and a piece of wood drilled to hold the probes in the water.I used probes from a Cyber Q2,a ProComm 4, a stoker and a thermoworks and check with a thermo pen. The results

Pit 277
Cyber Q probe one 183 Probe two 187
Pro Com4 Probe one 179 Probe two 193
Stoker Probe one 172 Probe two 172
Thermo Works 172 Pen170

Test two
Pit 350
Cyber Q Probe one 199 Probe two 211
Pro Com4 Probe one 209 Probe two 192
Stoker Probe one 188 Probe two 187
thermoworks 188 Pen 184

Test Three
pit 236
Cyber Q2 Probe one 192 Probe two 196
Pro Com4 Probe one 195 Probe two 182
Stoker Probe one 177 Probe two 176
Thermoworks 173 Pen 171

Here is the interesting part
Lid off three minutes and fan not running

Cyber Q2 Probe one 168 Probe two 168
Pro Com4 probe one 170 Probe two 170
Stoker probe one 172 probe two 172
thermoworks 173 pen 171

My conclusions are that the heat of the pit affects the Guru probes a lot. Where the others only a few degrees.If someone else would try this test
with the Guru I would be interested in your findings. It looks like a quick test is having the lid off a few minutes and seeing if the temps drops like in my test.Also probe two on the ProCom4 was the old style non braided probe.

 

[Josh Greer]

Assuming Guru uses Thermocouples for their heat sensor, it could be 2 (or more) issues:
1.) Thermocouple uses cold joint compensation to calculate the final temp. If that cold joint (probably on the guru) is getting hot or overly cold, it can effect the result. Possibly move your guru or wrap some insulation around it.
2.) Thermocouples can give false readings due to electrical conductivity. Try to shield the jacket from contact with the smoker with a cork or some other non-conductive insulator.

See if either one of these 2 options makes a difference.