We recently purchased the DT80-4 to work in low temperature to read T type thermocouple probes. It is connected with 2 thermocouples on the main module and 40 thermocouples on the CEM20 module. The main and extension module are both working in about -20C environment and 40% relative humidity. To calibration the thermocouples, we use glycol to simulate the low temperature situation. When we put some of the thermocouple probes into glycol at temperature below 0C, the other ones which are at room temperature have lower readings simultaneously which is approximately 2C lower. And also the probes in glycol reads 4-5C lower temperature than our standard thermometer. Do you have an idea what went wrong? Thanks for the help!