Yanche wrote:The temperature sensor is a thermocouple sensor. Type K. There was one member that suggested that they are now using Type J, which has a narrower temperature range.
By this do you mean greater precision for the J thermocouple?
Precision, no. Using any thermocouple, especially a type K, is a poor choice in this application. The type K has a wide dynamic range, −200 °C to +1250 °C / -330 °F to +2460 °F and a sensitivity of approximately 41 µV/°C. Yes, that's microvolts per degree C, i.e. millionths of a volt per degree C. So the electronics part of the temperature measuring device has to be capable of measuring very small voltages, something that's not easy to do accurately. The type J has a more limited range, −40 to +750 °C, and greater sensitivity 55 µV/°C. A better choice, but sill a bad choice.
Look at this way. Your car's speedometer reads 0 to 100, but if you only drive in school zones that have a posted speed limit of 20. You want is to read around 20 in tenths, but you can't. Wrong choice of instrument. That's what applies here.