Turn off the burner control switch, which is a toggle switch in the upper right corner of the Jotul, at the front. Close the gas valve connected to the back of the Jotul and wait for the stove to cool.
Remove the rating plate, which is a square panel on the back of the Jotul, using the nut driver to take out the bolts. The thermocouple is mounted vertically to the immediate right of the pilot valve when viewing the inside of the Jotul from the rear.
Loosen the two screws holding the Y-shaped clips wired to the thermocouple. The screws are below the thermocouple. Pull out each wired Y-clip.
Unscrew the retainer nut that secures the thermocouple to the mounting bracket. Pull the old thermocouple straight up, removing the part and the two attached wires. Make a note of which screw connects to the black wire and the white wire.
Insert the two wires on the new thermocouple into the hole in the mounting bracket. Thread each wire one at a time through the retainer nut and slip the Y-clip on each wire beneath their respective screw heads. Tighten the screws.
Tighten the retainer nut to the threads on the bottom of the thermocouple to lock it in position next to the pilot light.
Replace the rating plate on the back of the Jotul with the bolts and nut driver.
Open the gas valve in the line connected to the back of the Jotul.