I have a Jotul F3 and the manual says on top of the stove is where you put the thermometer. But alot of info out there says put it on the flue pipe. My neighbor has it there but I don't know what temp he looks for, never asked. Not even sure what that temp should be and my pipe is going into a wall thimble and chimney block, clay lined chimney. Jotul says stove thermometer should be 400 to 600. I bought a spring thermometer last year with the stove and have been using on the stove since. If the stove is up to 600 what should the pipe be.