[Archived]

bottom right of your pic in background is a stack of black cubes with red button looking on top(not button by way) with key on check and see if 3rd from bottom has power to it. Converters modify systems but on prevost level low that must have power before any thing else in suspension works.

[JIM]

Bob,

I believe Eric’s issue is not related to airing anything on the Prevost side, but getting air from the Prevost aux tank to the house. Apparently running the aux compressor however does open the path.

Questions…….If the system is pressurized by running the engine does air get to any house functions such as doors, dump valves, etc? Can if be assumed the bus will function in all level low and driving settings? Or more precisely everything on the bus accessory circuit works such as belt tensioners, door lock suspension, retarder, etc?

If running the aux compressor does get house functions to work, do they work all the time after that?

[John]

I may be wrong, but the Versa Valve comes to mind. It is the one in your picture with the two blue wires.

Anyway, I had one fail and it was newer than yours. The Versa Valve is a Liberty item.

Give Troy M a call at Liberty, FL, he will verify.

JIM

[JIM]

Jon, does the valve marked converter have a shut off like Marathon to separate the house and coach aux air?

Does Liberty plum that way, can’t tell buy the picture. Does the air flow to the house to the left of the valve?

And finally if that valve is not a shut off valve, if the coach aux air was empty, could you fill it from the aux

compressor or is there like a check valve in that valve marked converter? Thanx

[Archived]

What JIM calls the Versa Valve is a solenoid valve that is normally closed. Its function is to act as a check valve so when the compressor is not running air from the accessory air tank cannot bleed out through the aux. compressor.

If it fails to open (it is energized to open when the pressure switch calls for the compressor to run) then the compressor will not pressurize the accessory tank.

To Joe’s question the house and Prevost systems are not isolated from one another on a Liberty because both use the same accessory tank. What I am thinking is a check valve or proteciton valve installed by Prevost has failed and is not opening to allow air from the tank to reach the Liberty house manifold. The protection valve I believe is installed by Prevost to prevent converter system gorss leaks from draining the accessory tank, which serves multiple Prevost functions.

[Archived]

Eric,

We aasume the thumb valve at the converter connection is open (on) correct?

[Archived]

After a month of being parked, we used the bus. Before starting the engine, the Aux pressure
gauge located to the right of my dash, was at zero. Primary and Secondary gauges were both at
110. After engine start, the Primary and
Secondary were at 120 and the Aux pressure was still at zero. Suspension raised and lowered fine. Nothing air related in the bus worked except the
driver’s seat. Then I turned the Aux compressor
circuit breaker on, the gauge quickly went from 0 to 90 and cycled off. I was
then able to use air items in the bus, but the Aux gauge quickly dropped off,
and the Aux compressor came on. I also
noticed the air horn would only work for a few seconds, until the Aux compressor
got the pressure back to normal.

The only air I am getting on the Aux system inside the bus is
solely provided by the Aux compressor, regardless if the engine is running or
not. If I don’t use anything on the Aux
system, the Aux compressor will not come on for about 70 – 80 minutes, and when
it does come on, will run for about a minute.

There must be a safety valve that is designed to isolate a
leak on the converter side from the bus – this valve must not be opening, and allowing
my Aux system to get air from the bus. Where
is this valve?

[Archived]

Hi Tom – Yes, it should be on. I never touched it.

[Archived]

Eric,

I couldn’t pull up a pneumatic diagram for you specific coach, but from your description your system has some similarities to mine. My driver seat is on the Prevost side of the system and not off the Liberty manifold as an example.

What it sounds like is air is not getting past the protection valve installed by Prevost. Air from the accessory tank is reaching all Prevost systems including the suspension, belt tensioners, etc.

You can verify this by disconnecting the air line marked “converter”. If no air rushes out when you loosen it even with the accessory tank pressurized just move upstream until you find where air does escape as you loosen fittings. That will let you identify the issue.

I think the fact you show no air pressure is the air line to the gauge is downstream from the blockage.

If your coach has ever had a history of water in the pneumatic system it may be the reason for this issue. It might be you will encounter other similar types of issues until various components are replaced or repaired.

[Archived]

Thanks Jon. Is the valve marked “Converter” the bad valve?

[Fred F.]

Is it possible the downstream part of the aux air system has a leak and it takes both compressors to keep up? The reason for the question is you said the aux compressor will bring the pressure up but it falls off rapidly.

Mikee

[needtocamp]

maybe the check valve located on the compressor it self has failed. Not unusal. The whole air system is moisture sensative. A moist system produces what i call white rust (not ferous) but a white film that causes spools in norgren and othe air regulation valves to stick or fail. Aux air systems have the biggest impact on moisture induction into air system because of poor or no( not many with air dryer on aux air) air dryer control the moisture trapp in your picture needs to be drained often.

[Dick]

Eric, Start at that assembly. That is a protection valve. Work backwards.

Bob, the solrnoid valve is the Liberty way of providing a check valve against leakage through the compressor.

There is no air leak big enough to keep both compressors running. According to Eric the house aux compressor cycles on and off, I suspect rather frequently because the volume of the “pressure tank” it sees is only the volume of the house systems and air lines based on his description. There is no check valve that prevents aux compressor air from going back into the accessory tank because that is how the tank is pressurized when the coach is not running. I suspect, and Erci can verify this, if the accessory tank pressure is at zero, he can turn the aux compressor on and it will not pressurize the tank, so whatever blockage is in the system it is preventing accessory air flow to and from the house systems. The problem is in between where the accessory tank feeds the Prevost systems and the house system connection point.

[Corey]

OK – I will start at the “Converter” valve. Just to clarify, the Aux pressure will stay at pressue for over an hour. The pressue drops-off quick whenever I use, for example, the horn – will only work for a second or two. The only source of air is from the Aux compressor. Thank you for the help.

[Andy]

Eric call me if you want