[Richard]

If you push the Level button once. You are in manual mode for leveling. If you push it twice, it puts the HWH computer in Auto level. In auto level the computer will automatically deflate or inflate air bags to make the coach level. If left in Auto level, and the coach becomes in level, the brain will wake up and attempt to relevel the coach. When it does this, it turns the 120V compressor on.

Here is a tremendously over simplified air system explanation. All air supplied by the 120V compressor and engine driven compressor goes to the brake system first. The brake system consists of two isolated tanks. Those tanks are isolated by the Pressure Protection Valve. If there is zero pressure in any system, all air will go to the brake tanks UNTIL the tanks reach approximately 60 psi, then air will flow into both the brake tank system and the general SUPPLY system.

Everything but the brakes receives air from the Supply system. That includes travel mode, level mode, generator air bags, doors, and potties.