One of our test units and two other units in the field have been blowing fuses without any other issues. We have tracked the problem back to the spade connector on the fuse holder. The spade is wavy to promote contact but when it heats up, it wants to go back to flat and looses its connection with the connector on the wire.
When your running at above 3000 psi, turn off the compressor, unplug, then remove the cover and check to see if the connectors on the fuse holder are hot. If so let me know here. For good measure, if you have a soldering iron you can solder these connections and have no further issues.