My DDC-1's never shutdown, even under the abuse of cooling a TEC, and I think I know why. My rad is always after my blocks. The rad is the last thing in the loop before the res. So my pumps are always getting water that's already cooled. Even after being on for the last 48hrs straight, my DDC-1 isn't even warm to the touch. I should note that there is no airflow on the pump at all. My setup isn't in a case, it's running on top of a table. lol.