Digiboil Thermostat?

Hey I have a question for the group! Does anyone know what type of thermocouple the Digiboil uses?

I’m trying hook my K Type thermocouple to it and it’s reading an error - E2 short circuit.

The purpose is the have it read the temperature at the top of a still column vs. at the bottom of the pot.

Anyone ever done this before??

Thanks!