Hello,

So I posted this question on homeroasters forum but didn't have much luck, so I'm curious if anyone has any insight on this.

I'm having an issue with only one type of probe, the alt BT probe, and I'm not sure why. Eric S. was kind enough to send me a replacement, but I get the same results with the replacement. The reading of the alt BT probe gradually gets further and further apart from the standard BT probe as the temp gets higher. So at 100 degrees, the alt bt and bt read the same. At 200, they start to drift by about 25 degrees, by 300, 75 degrees (Those are rough numbers..). I'm not sure why its doing this, but I'd really like to get the alt bt probe working so I can do smaller batches.

Things I've tried:
1. I plugged both probes into my Thermoworks Blutherm duo and the probes read exactly the same at all temperatures.

2. I used the serial monitor to get readings, and they were similar to those in the artisan software.

3. Right now I use k-type female sockets, so I tried hard wiring and received the same results.

4. Tried different ports, same results.

Would anyone have any ideas as to why this is happening or what else I can do to troubleshoot?

is your problem with the board and not the thermocouple?

I'm not sure yet, that's what I'm trying to figure out. If the difference was 10 degree's I'd let it go, but when the difference is beyond 50 degrees with two probes that are about an inch apart, with no beans, that seams odd to me...no? If I'm wrong, someone please tell me.

Here are some data numbers to show the difference as the temp rises.

ALT BT BT
143 136.9
154.2 150.2
164.4 163.4
176.1 177.7
186.9 192.3
198.9 208
210.6 222.8
223.2 238.1
236.2 254.6
246.6 270.7
255.6 286.1
263.4 302
277 317.5
291.5 335
300.8 349.4
307.5 362.8
314.3 374.6
320 385.4
327.1 396
332.1 405.8
336.1 414.8
343.2 423.8
347.3 431.4

Just a shot in the dark here... some thermocouples have different temperature ranges, ie, they max out at different temps. A very common max for some is around 400F, and my experience is that these things get wildly inaccurate even when you're pretty far from the max. You could confirm this by running up the temperature to well over 400F as indicated by BT, and see if you can get alt BT to get anywhere near 400. If you can't, then maybe this is the problem.

For Rob - These thermocouples (Type K, grounded) are good for around 1500 F or higher which is certainly well above the temps in the Quest M3 roaster.

I was able to resolve the with the help of Eric S. Turns out there's an issue with the outlet the unit was plugged into.