Hi Piter112, I do not understand about the potentiometer, but if you want to share it, it would be curious. I don't know where you've put it, but I don't believe a good idea to let it connected instead of the probe to regulate your ... I suppose you have put it "to experiment", well as correction to the values I gave you, in cold, 3K, hot you can arrive to simulate it instead of 900, at 270 ohms
. Ohms up to 380 ohms