I have several customers whom I sold these to, and have had a lot of issues with those pumps. They are the ones with rubber tubes inside and rollers. I changed one over to the Fragramatics style that does not use any pump other than the air compressor. It was quite easy. Just changed out the hose and gun, and rerouted the supply hoses. No wiring changes were needed. My maintenance theory is that any time you can remove parts and have something work the same or better, do it. The next time you have pump issues, just throw it away.