What should I do if the Miller 350P overheats during welding?

If the unit overheats, thermistors RT1 and RT2 will open, stopping the output while the cooling fan continues to run. You must wait at least fifteen minutes for the unit to cool before attempting to weld again. To prevent future overheating, reduce amperage or voltage, or reduce the duty cycle before resuming welding, as exceeding the duty cycle can damage the unit and void warranty. (Pages 9-10, 30)