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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 Steve.  I just sent your schematic to my pictures and was able to make a full page copy from that.
Steve,

Can you add an arrow to the 120V pump in your picture? On my coach, the front seals do not inflate with just the 12V. (If I dump all the air, and just turn on the 12V, I will not have any air in the front seals). I suspect a bad check valve, or some other issue...but have not been able to trace the air lines. With this picture, I may be able to figure it out.

Thanks!
bill
Bill,
Keep in mind the first rule of owning a Newell--"no two Newells are the same".  

The 120 psi air is fed in from the line that is stubbed off in my drawing.  That line can receive air from either the engine and/or 120V compressors.  I haven't done a schematic for the 120V air compressor yet and it is not part of my drawing.

I don't think you will find any check valves in the slide seal air lines--"think" being the key word.  I would start at the regulator for one of my front slide seals (pick the easiest) and follow the air line and document where it goes.  If it is connected to the 12V air pump, sooner or later you will end up following a line back to the 12V pump or the 3 gallon air tank in the right wheel well.  If you need any help feel free to call me.

Chappell,
Glad you could download it yourself.
(12-31-2015, 08:25 AM)rheavn Wrote: [ -> ]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.

Yes..I would like a copy.. Markgmc3@aol.com

Thank u.....hope it is the same on my 1999

Mark
(12-31-2015, 08:25 AM)rheavn Wrote: [ -> ]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
Ok, first you have a big leak. A leak so big that the 120V or 12V output will not overcome it. Also, with a leak that big, both of the little compressors may have worn themselves out trying to keep up.

Second, you are exactly right about turning on the key. When you turn on the key it opens the travel solenoids to the airbags. They usually will take about 90 psi to "float" the coach. If the system pressure is less than the pressure in the airbags, then air will flow from the airbags through the travel solenoids, through the height control valves and into the system.

Start by piping the 120V compressor into a deadhead with a gauge. Determine if the pump is actually capable of building pressure.
On the 12V compressor, confirm that you have 12V power on the pressure control switch at the pump. The switch is commonly referred to as the well pump switch. It is usuall a grey box about 2 by 3 inches. Wires will originate in that switch and go directly to the pump to turn it on and off. Start the diagnosis by determing if the swtich has power.
(11-28-2017, 06:48 PM)Richard Wrote: [ -> ]Ok, first you have a big leak. A leak so big that the 120V or 12V output will not overcome it. Also, with a leak that big, both of the little compressors may have worn themselves out trying to keep up.

Second, you are exactly right about turning on the key. When you turn on the key it opens the travel solenoids to the airbags. They usually will take about 90 psi to "float" the coach. If the system pressure is less than the pressure in the airbags, then air will flow from the airbags through the travel solenoids, through the height control valves and into the system.

Start by piping the 120V compressor into a deadhead with a gauge. Determine if the pump is actually capable of building pressure.
On the 12V compressor, confirm that you have 12V power on the pressure control switch at the pump. The switch is commonly referred to as the well pump switch. It is usuall a grey box about 2 by 3 inches. Wires will originate in that switch and go directly to the pump to turn it on and off.  Start the diagnosis by determing if the swtich has power.
Richard. thanks for the advice. While the pumps do come on I have not checked to see if they are working properly. I will pick up a gauge today and let you know what I find as soon as I can get to it.
As would tell anyone, finding and fixing air leaks is not easy. Unlike electrical problems where we can measure at many points in a system, we are blind to what is really going on other than losing air pressure somewhere.

So we quite often have to "break into" the air system plumbing to determine where the problem lies. Many of us have built or collected a small assortment of air line fittings, gauges, and valves to make this a routine exercise.

The methodical approach of isolating and testing works. The random replacement of fittings, valves, and cylinders is expensive and does not produce satisfying results.

That being said there are a few areas that commonly cause air leaks of consequence. The electric valves that operate the dump valves, a hole in a slide seal, the bode door system, connections at the air ride seat, and the microphor potties are quick places to check.

If you haven't you might want to study this thread http://newellgurus.com/showthread.php?tid=2690 and this one http://newellgurus.com/showthread.php?tid=2677&page=2

And the best one of all " can you find your most excellent thread on the system and the air leak isolators? I couldn't find it in a quick search this morn."

That thread should be a sticky at the top of air systems category.
If this is not the thread you were referring to, let me know.

http://newellgurus.com/showthread.php?tid=2705
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