I understand we have a very old TREND IQ151+ system but we are struggling to find the correct thermistor type for our application. The thermistor is required is required to monitor tunnel temperature for the refrigeration to freeze ice cream.
I have looked at the various Thermistors that TREND make but none seem to have a low limit of at least -40 or maybe I am reading the specs of the thermistor wrong.

can anybody please help.

thanks