How to connect a Type 'K' Thermocouple to a GTR v1.0
Overview
GTR v1.0 boards should have support for Type ‘K’ thermocouples.
The chip shown below in red, is the MAX31855K ‘K’ type thermocouple support.

Config.g changes
To use the Type ‘K’ Thermocouple on your hotend, use the following code in config.g
M308 S1 P"PH_9" Y"thermocouple-max31855"
Make sure to (re)run the PID-tuning, e.g. M303 T0 S20.