Hi Wade,
Below is from the Cookshack Forum it may help? Or is yours shutting down electrically? If it is you may have proven that the controller is Ok and it is something else triggering the shut down
Something else to be aware of with the FEC-120, is it likes a big load. If you want to smoke a few racks of ribs at 225 degrees, you may find the smoker sometimes puts itself out. Reason being the FEC is such an efficient smoker, that it will go to over 225 degrees easily, and stop feeding pellets until temp comes down. Sometimes the fire pellets will be burned up, and when the smoker decides it's time to feed pellets again, the fire isn't there. This has happened multiple times, and Cookshack concurs with my experiences - either raise temp up a bit or increase the load.
As an example, we smoke a full prime for our Ribeye sandwiches early in the week. I like to smoke it low and slow to rare. TO keep the smoker going around 230 to 235, I load a full pan of ice on the lower shelf to keep the smoker producing smoke and fire - if not, it would put itself out.