Not familiar with your compressor. Have you checked every fitting for leaks? Where is the check valve? Is the check valve integral to the compressor? It could be leaking through the compressor. Use a leak detection type soap for every fitting.
And, eventually the compressor will burn out if it runs continously. Fortunately mine was covered under warranty. They used to be in the rear axle area but many people complained because it was near the sleeping area, so they moved it up front. If you leave your air leveling system on, the computer "wakes" every hour to check if you're level. If you are, it goes back to sleep. If not, it activates the compressor to level your coach...you can shut if off as twomed described above.....hope this helps...Dennis
On edit: you can install rubber bushings over the bolts that attach the compressor to the frame which will reduce the noise from the compressor. I had Monaco techs do that with mine when they installed the new one and you really have to strain to hear it.....D
I am going thru that right now Dennis. Glad I have the extended warranty, as they are going to replace the whole unit and the distribution manifold. Cost is over $2000. I'm going to tell the mechanic about the rubber bushings. Thanks for the tip.