Aux Air Pressure?

[dreamchasers]

What Aux Air pressure does most use when the coach is parked? For example, when the coach engine is not running and the coach is parked. What aux air pressure does the air compressor come on and off?

Mine seems to come on at ~80 and off at ~100 psi.

Hector

[phorner]

Hector,

Mine is similar..... on at 60 off at 90.

That being said, we only need aux air while parked to operate the bed lift.

And, of course, airing up the occasional bicycle tire :D

[truk4u]

Hector,

60/100 for toilet only.

[Jon Wehrenberg]

I have backed mine down to on at 40, off at 80.

At the lower pressures the pump doesn't work as hard yet everything still works, doors, bed lift, door lock, floor slide (not needed, but it still works) generator air bags, and dump valve.

[Reagan Sirmons]

Guys,
I could not figure out how to start a new subject so I hope this gets posted on this old thread. For those who might note my posts are more regular over the last 60 days...this is what happens when a AAA personality ends up with half a day every day at present free to tinker...
Here goes: When I turn the ignition key to the "on" position, there is a distinct hissing sound coming from the right side drive axle area. When I turn "off" the key, it stops. I can run the engine and turn off the key and there is no escaping air. HOWEVER, when I turn the ignition key to "on" and the hissing begins, I can reach up to the Country Coach installed leveling device high on the front ceiling and turn it on...the hissing then stops immediately. The leveling device switch, when activated, shuts the escaping air off. If the air is allowed to escape, the air pressure in the on board air compressor declines.
The coach does not have any leaking air bags and the selector switch on the left panel is in the correct position. ... what does anyone think is causing the hissing escaping air when I turn the key on? Is there a leveling device at this location? I am not about to get under this thing to look even though I have bus blocks. Something tells me that potentially varying air pressure and weight do not mix well.
Thanks for your thoughts.
Pres

[Gil_J]

Reagan,

First, congrats on the free time!

When the key is off the air bags are sealed from the rest on the bus' air system. When you turn the key on the bags are being controlled by the ride height valves. When the key is on your HWH leveling system goes into "drive" mode, which puts the Prevost system in control. With the key on you can turn on the HWH level system which takes control of the bags and takes the ride height adjusters out of the picture. So, your symptoms suggest the hissing could be from the ride height valve. If so, let the coach get to ride height and see if the hissing goes away.

You should be able to reach in front of the drive tires and feel the air coming from the valve, if this is the leak. Here's what it looks like. The hose aimed straight down is attached to the exhaust port and would be were it's leaking, if it's the internal piston and o-ring that is leaking. You should be able to safely do this without getting under the bus.


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[Reagan Sirmons]

Gil,
Absolutely great! I will test this tomorrow. That has to be where the hissing is originating.
I at least know what I am looking for... I changed these out on the '87 Newell I totally rebuilt in 2004... at least I have the idea.
Thanks a lot for your kind response. Where do you guys live? Is it in a warmer climate? ... we are in Houston and had some cold weather for us last night...
it delayed the tee times this morning...
Best,
Reagan

[Gil_J]

Houston, and Texas in general, seems to have gotten colder the last couple of years.

I'm on Florida's Nature Coast, about 75 miles north of Tampa. So far, the whether has been good, but there were a couple of morning in the past few weeks weer we hit 40 degrees. The good news here is if it gets too cold we can drive south. Unless you want to cross the border, you don't have too much more south left.

[Reagan Sirmons]

Gil, I just went to the coach and for the first time ever, the coach was leaning to the left. I cranked the coach and let it run for 5 minutes. I then cut the engine off ... no leak....at least one that I could hear..... I then turned on the key and the hissing began. I found both ride adjustment valves and neither one is leaking. The leaking is very pronounced and is coming from somewhere between the two sets of air bags (starboard and port) If I could guess, it is midway or is closer to the port side ...the side to which the bus was leaning. There seems to be a couple of chambers under there... I definitely could not tell for sure but it is as if there is an open valve....so its a big escaping amount of air. Tomorrow, I am taking the coach to a truck shop that has a long pit under the coach. I will then be able to see exactly where the air is coming from. It is so pronounced that it will be very evident, I am certain. I just cannot see the source without getting under this thing and that's not going to happen while it's in the warehouse.
If you have any thoughts for my search, I will listen intently but for now...I will have to wait until tomorrow. I may be wrong but neither of the air bags seem to be a part of this problem even though the air finally went down on one side for the first time ever.
Thank you again...
By the way, we can go 200 miles South of here and never be out of Texas.
Nonetheless, I was talking to some people today from Tampa... I have a relationship with a group there... we meet in Sarasota on occasion... if we meet any time soon, I will bring the coach and we might get together.
Very best... I will keep you posted on the mystery leak but let me know your thoughts if any.
Pres

[Reagan Sirmons]

Took the coach to a shop and put it on a rack. In front of the over-the-road evaporator coil of the Country Coach installation which hangs down between the drive axle tires on the drive axle, there is a support beam going across the coach. Attached to the wall forward of the beam and opposite the evaporator coil is a valve with three or four hoses connected to it. Two of the hoses go out the bottom and curl upward through a "gathering" of other hoses and electrical wires. One of these has the hole in it. I assume these go to the front to the air compressor but am not certain. Above the valve and out of reach...as the hoses go to the gathered hoses and wires, the two hoses from the valve are clamped together by a plastic tie down that has worked a hole into the hose itself. The air escaping is prolific with the key turned on but stops if I engage the CC leveling system. Once the coach stops and the engine is off, the air doe not escape. I, of course, assume that the air is escaping while the engine is running but for obvious reasons of noise and vibrations could not tell. I assume I will call the CC folks who represent that they can advise CC owners for a fee. I certainly think they would be the ones to tell me if the hoses go to the compressor..... that is at least twenty two feet forward of the valve. My only thought at this time is to determine if these two hoses go all the way and if new hoses attached to them could be pulled through the portals. The answer is no if they are clamped anywhere along the way.


1349013489

The picture on the left is looking up from the bottom. The hose with the hole in it comes off of the bottom (blue in appearance here) and goes directly above the valve about 16 to 18 inches before it goes out of sight as can be seen in the second picture. The picture on the right shows the actual hole (the black area). This also shows the gathering area I was describing. . It is a hard, hard thing to get to. I could not reach it even standing with my shoulder up against the support beam. Are these wires reachable from any other area?
Very interesting situation. It seems that these hoses were put in place and this coach built around them. I wonder if these hoses go through the area where the water heaters are and could be reached if I took off the panels?

Thanks to all who have been following this.
Pres

[Joe Camper]

Your line thats leaking is the one that is COMMING FROM the side of the ride height valve in that rear corner as the photo Gill posted. Not to or from the front. There should be 2 valves there side by side. Whatever valve it is attatched to thats the corrisponding rear corner the line comes from.

With the correct supports in place the tires do not even need to be removed thats less than an hours work and about 20 bucks in plastic 3/8 line and fittings. The fitting at the ride hwight valve end is 1/4 pipe to 3/8 compression. The fitting at the valve is 3/8 pipe to 3/8 compression

The other line coming IN the bottom of that norgren spool valve is COMING from the norgrin air manifold under the drivers area it produces air or lets it out when u hit the up and down button at the drivers seat or when Iin auto level. The top line is GOING to the air bag.

The 2 smaller black 1/4 in lines on the ends r the signal lines. One is energized when in driving mode the other is energized when u r in level low manually setting height or when the cc auto level is turned on.



When u turn the key off neither signal is present. If the valve is completly air tight u can pull every line out of that valve accept the top one going to the air bag and that valve should maintain pressure to that perticular corner of the suspension. Thats actually the way to bench test those norgrens right on the bus.

[Gil_J]

Joe is pretty much king of the Prevost air systems, so little doubt in questioning what he says.

The Prevost air system is thought by many to be the most complex sub system on the bus. IMHO, that's only because there isn't a good description stating the logic and controls. There is a drawing available from Prevost. And as good as it is, it's still hard to fully understand what you're looking at. As just one example of something missing from that drawing for the XL is the check valves. Not knowing where these are makes it that much difficult to fully understand the logic. Even the self proclaimed experts have stumbled and provided misinformation. These are people that pride themselves in doing most everything on their own coaches and having replaced every Norgren air control valve on the bus.

I spent some time with a Prevost Service manager that really knows his stuff. When we tried to dig into the details of the air system we used both the air drawing and the illustrated parts breakdown. What we discovered were both the answers and more questions. The questions came from differences from the two illustrations. Air lines were not run from the same places, in a few instances. Once the logic is understood, it becomes apparent that both drawings achieved the same goals and exactly the same functionality even though the air lines were ran from different places.

What I can tell you from the drawings and your description are two Norgren valves that are 5-port valves located where you describe, is that they are Level Low control valves. And as Joe stated they have air lines to the air bags and the 5 port electric/air solenoid manifold in the lower bay under the driver's location. They control the air flow to the suspension based on whether the level low is engaged or the ride height control valves are engaged. CC uses the HWH controller for automatic levelling when parked and it simply takes over the functionality of the level low control switches that are located below the driver's window or hidden in the electrical bay just below the driver's window. I know that the blue air line would be specific to the suspension system. What I couldn't tell you is which line is on which port without looking at it or assuming the diagram has the Norgren valves illustrated in the as installed.

Let us know how the repair goes. If the failure was due to chaffing, all of us XL owners should take a look at this hose.

[Reagan Sirmons]

Thank you for all of the great guidance.
On this one, I am going to see where I go with it by myself but have a mechanic standing by just in case. The explanation is a relief.
The help is truly, greatly appreciated.
I will keep you posted.

I owe you guys some Cajun Chicken Spaghetti or at least some true Texas Bar BQ. On that subject on a lighter note, I just noted in my Wall Street Journal of yesterday that a fellow wrote an article on Bar B Q in Austin, Texas. He stated that when he picked up the brisket...it literally fell off of the bone....

Q: What is wrong with that statement?
A: Brisket is a combination of two muscles and does not have a bone....

I wonder if the guys in NYC will catch that one?

Pres

[dale farley]

We did have some excellent diagrams/schematics on here that Hector had developed. I don't know why they are still not in the Articles section? I think it was deleted because the link was no longer active.
Hopefully, we can get Hector to re-post the information. He is also very knowledgeable or the air system.

[Reagan Sirmons]

I found the hoses and the ride height adjustment valves to which they are connected. One cannot tell which hoses go where because of the harness...... until they can be disassembled from the harness and followed as to their direction.

I have decided this is beyond my risk profile and do not want to be under the coach without professional assistance and supervision. Therefore, we have elected to fully support the coach with appropriate coach supports and two 20M# jacks. We will then pull the driver's side duel tires off to gain complete access to the offending hoses. From this, we will hopefully be able to tell the actual hoses with the holes in them and which of the ride height valves they service. I can definitely see that this is a job that is perfunctory but the circumstance of being under this thing bothers me. I am leaving this to the professional.

Thanks again to everyone....
Pres

[Reagan Sirmons]

Tonight, the mechanic and I determined the line that is leaking is indeed one of the lines that goes up from a canister type of object and through a rubber "boot" and then goes forward through the bays toward the air compressor. It is leaking at exactly the rubber boot. The leak is not the blue line I first thought was leaking. We looked in the next bay forward on both sides of the coach to find where the boot goes.... On the passenger's side, we have the bank of batteries but can see what appears to be the hoses coming from the rubber boot and going across the top of the bay toward the front of the coach. You have to be about 3 feet 7"" and weight about 50 lbs to be able to reach them...There may be only a very slight chance we could determine which hose is the one leaking and pull it back and cut it in the battery bay. If so, we would put a "quick connect on the front end and replace the entire hose going back through the wall and the boot to its point of beginning.
Any thoughts on this? ... I assume these hoses would be very hard to pull through for any distance.
As a question...how does anyone replace one of these hoses completely at all if they fail like this?
All the mechanic kept saying while he was under the coach was "whew!"...
Sorry to bother you guys but this one has us stumped. We can't get to these hoses. Thoughts would be appreciated....greatly.
Very best,
Pres

[Joe Camper]

If u r story is still the leak is present when u go into driving mode and stops when u go into leveling mode

AND

u r reasonably sure it is in the location of


the rear spool valves

AND

it is not the blue 3/8 plastic line between the norgren and the ride height valve

THEN

The only other line energized in drive mode in that location would be the black 1/4 in signal line going to that norgren.

[Gil_J]

Reagan,

Ideally you could pull enough hose so you could put a coupler on the forward direction line and a short replacement line to the Norgren air valve. The reality may be that this is not possible.

It is not uncommon to abandoned-in-place wiring and plumbing lines that are simply too difficult to remove. Instead, a new line is ran. Before you can run a new line you need to know where the two end points of the line you're wanting to replace. In your case, there are two 1/4" black lines running forward and only one needs to be replaced; which one is the question. The two lines both run to the bay under the driver's window. Most of the lines run to the electric solenoid controlled Norgren that has 5 electric solenoids. Let's number these solenoid controlled ports 1 through 5 with 5 being the one closest to the end of the manifold that has a hose connection. If the rear Norgren that has the leaking hose is on the driver's side then the two hoses go to the port 3 of the forward Norgren (the one with a T fitting) and the port 5, closest to the end with an end connection. If the rear Norgren with the leaking hose is on the passenger side then one of the two hoses go port 4. The other hose goes to one of the air only Norgrens next to the electric solenoid operated Norgren. These 2 valves are identical with one having 3 connections used and the other having 4 connections used. The one with 4 connections should have a T fitting. One of the hoses on that T fitting goes to the other like Norgren and the other goes to the rear passenger side Norgren.

Okay, now with that you know where the other end of the hose can be, it's time to identify which on of the 2 it is. Simply disconnect both of the hoses up front and blow air through them, 40psi should be more than enough.. One will have that air existing the leak.

Now simply run a hose the most convenient and protected route from front to rear. My guess is that path will be through the center overhead of the first bay and possibly the second bay. It will then come into the third bay, battery side, and be routed along the ceiling of that bay. I'm guessing you can penetrate the rear wall in a location that will allow you to feed the hose through and keep it away from the wheel well area and any other area that looks like it could be subject to road debris. As an alternative, it might be possible to bring the line down into the generator bay and exit the bottom where it could be run along side the steel member that protects the generator exhaust. If you take this route, and it's not preferred, run the hose inside a piece of electrical conduit and use fasteners every 12" to mount the conduit to the metal support opposite side of the exhaust.

Okay, let's say you don't want to make the new run. The battery box can be removed. I would really not want to take it out given the level effort of removing the batteries, inverters, and all connections, but it is possible.

Good luck,

[Reagan Sirmons]

Gentlemen, especially Gil, Joe and another of my new heroes....Hector....
After all of your superb guidance, we determined we could not access the hose anywhere beyond the forward wall against the battery bay and the leak was actually directly in the collecting boot going through the wall. We were able to pull about 4 inches of the 1/4" tubing back into the drive axle area. We attached a "brass in-line quick-connect" to a fresh 1/4" air line and then tried to get the older airline into the other end of the "quick-connect"....it was a task because we literally could not reach it. We took two long handled pliers and gently grabbed the old end with one set and the fitting with the other and forced them together untouched by human hands.... We felt the fitting was very secure and that the integrity of the air line was sufficient to hold. Then, we connected the new line to the valve using new fittings. As always, you don't know until the final test. After pulling and stressing the connection, we built up the pressure and turned on the key. SUCCESS!. NO LEAKS!
The reason this was so important was that if we could not attach to the remaining end...there was literally no choice but to have to run a complete line from front to back with all that involves.

Joe, I appreciate your careful explanations and Gil, as always, you gave great, thorough guidance. HECTOR...I can only say thank you for all of your efforts and for taking the initiative of providing me with the coach's complete schematics and other information. What a super team effort.

The leak was actually a "flake" out of the skin of the hose itself. It was not greater than a 1/64th" spot. The line wasn't broken and was not "penetrated" by any object. It gave way where the tie down had a grip on it.

Thanks again to all and I hope anyone reading this enjoys the information and might be able to avoid similar issues in the future or at least solve any issues more easily.

The list for the Cajun Chicken Spaghetti is growing.

Best,
Pres

[Gil_J]

Great news Reagan.

I wonder which air drawing Hector gave you. The one found on the Prevost site under pneumatic drawing section has too much on it for its size to be used for real troubleshooting. It is good, but it would be much better if it was drawn to a much larger scale with more details. There are more detailed drawings in the parts breakdown. In the parts breakdown there is a much more detailed drawing solely on the level low suspension lines and components. Even with its detail, it doesn't have everything. As an example, it illustrates the rear ride height valves but not the check valves on the ride height valves..

As much as I'd like more details in some of Prevost drawings I won't complain. I think we should all be thankful we have access to this level of detail.