If you want to set it back to factory default remove the batteries hold the down adjustment button (the up down button to adjust wattage or temp changes) slip the batteries back in while holding the down button and close the battery door. This will put it back to factory settings. I'm pretty sure factory settings for wattage mode is 40 Watts with 80 Watts preheat for 0.10 seconds.
Hope this helps
Hope this helps