[Deper10]

Here is the schematic of the system & shows how it ties into the main air supply system. 

Attached is the 12V air system and how it interacts with the main air system.  The 12V air pump only puts out 60 psi.  The main air system puts out 120 psi.

To make things easier start with the main air system having no air pressure.  Follow the air from the 12V air pump and you'll see how it pressurizes both slide seal regulators, both of my toilets, both pockets doors and the 3 gallon air tank in the right wheel well to 60 psi.  Note how the check valve on "T" #3 on the air tank will not allow air to exit into the main supply system.  

Now energize the main air system with 120 psi of air.  The stronger air is supplied from the stubbed off main line and energizes both side dump valve solenoids with 120 psi.  The stronger air can now enter the 3 gallon air tank, through the check valve, and boost its pressure to 120 psi.  120 psi air now goes to both slide seal regulators.  The stronger air enters the 12V air pump four way and tells the pressure switch that there is more than 60 psi so no reason to turn the pump on.  The 120 psi air goes through the 12V air pump regulator & is reduced to 60 psi and supplies both toilets, and both pocket doors with 60 psi air.

If any one wants a copy they can print send me an email.

Thanks for the 12v system information and schematic. Do you happen to have a schematic for the 120 compressor? I am having an issue with both of them. With the motor running the system pumps up to about 110 PSI after shutting it off, it will drop to 70 psi in about 45 min without using any of the air operated doors or toilet. At 70 the 120 kicks on however it does not build up any pressure and I have not been able to find any air leaks yet. As for the 12v it simply does not come on at all yet if I run power directly to it, it works fine but also does not build pressure. One other thing that I don't understand is when the pressure gauge is reading 0, if I turn the key to the on position, without starting the motor, the gauge will build up to about 50 psi without any compressors coming on. It seems to be taking air from the front air bags, as the front end will drop by about 1/2" on both sides. Any ideas?
Thanks
Dario Perini
Coach #581  2001