First step.... Remove the press from current!

The function of the thermocouple can be measured with a multimeter

You have to adjust the multimeter on mV . On many multimeter you can also measure the temperature. 

In advance you just need to measure on both ends of the thermocouple(silver encapsulated wires)!

value mV value C°

0,08mV ca. 27°C

ca. 1 mV ca. 50°C

ca. 3,9mV ca. 120°C