I put a "T" in the line and can fill the tank from an external source, but once it has some air in it, the pressure switch (on at 90#, off at 120#) keeps the run times relatively short. As it happens I have a Thomas compressor, but as long as you don't have any leaks and don't run it way down, it should work without overheating. Mine is under the truck, and gets lots of air when moving, so that likely helps keep it cool tooo. .