Aux compressor

[lewpopp]

A couple weeks ago my aux compressor was coming on about every 5-10 minutes. I had replaced it about 5-6 yrs ago and thought it was that time again. I fooled with the simple parts of the front system to see if there were any leaks there and at the toilet and found none. I turned the compressor off because it was getting hot and it needed a rest. Later that night I turned it on to build up the pressure to flush the john and it pumped up and turned off just like normal. The went on the next few days but I went ahead and ordered another compressor. For about 10 days I had no problem and today it happened again. After it ran again, cycling every 2 minutes I turned it off again. I just turned it back on(5 hrs later) and it shout down and seems to hold the pressure.

I am thinking that the baffle in the compressor is weak and there is air leaking by that area. Can hear no leaks elsewhere. Well, I do have the other compresor to install. Is that what you would do?

[Orren Zook]

Lew,
I rebuilt my compressor for about 70 dollars. I first tried a piston type compressor that we had here as a replacement but it made too much noise to suit me. I was able to get the complete rebuild kit for the rotary compressor with shipping for under $70 earlier this year. I'll post the kit and telephone numbers and in the morning. I used their distributor in Pittsburgh and had the kit within two days of ordering. The rebuild took about 20 minutes from start to finish and was pretty easy.

[adamdegraff]

Lew,
I was just about to put up the same post. No kidding. Almost the exact same thing happened to me, except that now that mine has started working again, it continues to work... but I'm afraid that it will go back to running and running and overheat or cause a fire. That bay was SO hot after it ran for what was probably like 6 straight hours.

I'll let you know if it acts up again. Curious.

Adam

[Ray Davis]

It seems like they should almost have a timer inline with the power to these units. So at least it wouldn't run forever?

[Jon Wehrenberg]

Usually when a compressor kicks on and off frequently it is an indication of an air leak in the aux system.

Having said that however, it is also possible the pressure switch is set too high and the compressor has to run almost continuously to reach the pressure set point. When some compressors run too long they shut themselves off because they have some thermal overload protection.

Before I would replace a compressor I would first determine if there were system leaks. If none, or if the leakdown rate is minimal, then the next step would be to determine if the pressure switch was set at or above the compressor output limits. If the compressor is capable of 90 PSI, the switch needs to be set at some lower value so the compressor isn't running hard to try to reach a switch setting just below its maximum capability. As a compressor ages the maximum capability will decrease.

To measure the leak down rate run the bus engine (and thus the engine driven compressor) until it is at the maximum, and then time the loss of pressure in the system to determine if the problem is an air loss or some other cause.

[truk4u]

Good advise from Jon, my compressor is set to shut off at 120 lbs. No need to have that kind of pressure just to run a toilet and/or pocket doors. Jim Keller's aux compressor was like mine and the regulator was not adjustable. He got one at the Depot and set it for a lower shut off pressure and all was good.

[lewpopp]

I will run the engine in the AM . As I recall, the highest pressure the guage got up to was about 110 but try as I might I couldn't get enough pressure out of it to take my tires over 95. We'll see tomorrow what that brings.

There is a fellow who showed up as a(good) neighbor and he will check out the regulator or whatever that is mounted on the top of the old compressor.

Thanks for your help so far.

[lewpopp]

Well, I ran the engine and the pressure came up to 120# and wavered there for about 15 minutes.

Prior to turning the engine off we bled the air down and the engine kept up with the loss.

When I turned the engine off, the pressure was about 117 and slowly ( very slowly ) fell to 70# and stayed there for a long time and about 3 hours later it stayed at 67.

I guess we have decided to wait before we replace the motor because we do not know the reasons for the irratic actions of the compressor.

I got thinking that the valves in the Norgrens would not leak when the pressure leaked down to, say 70#, and would seat. I know absolutely "zilch" about them. Maybe the reason for the cycling of the compressor was due to them not seating even at lower levels of pressure. There is really no place within reason around here where I could take this. Presently everything is quiet and aired up.

[Jon Wehrenberg]

Lew, when you are shut down the Norgrens may leak and the end result will be you will lean or the front will go down. But the Norgrens have nothing to do with holding auxiliary air system pressure. They only function to retain air pressure in your air bags and the aux system pressure can go to zero and you air bags will still be inflated, and conversely your air bags can leak down until they are completely deflated and your aux air system can still be at max pressure.

If you are losing aux air pressure (and you are) the source of the leak is somewhere other than the Norgrens or suspension UNLESS YOU HAVE A "KEY OFF" AUTOMATIC LEVELING FEATURE WHICH KEEPS THE BUS LEVEL AT ALL TIMES AND REQUIRES THE COMPRESSOR TO BE TURNED ON TO MAINTAIN SYSTEM PRESSURE.

We had a feature like that in our old Liberty, but we just left the switch in the "road" or driving position to disable it.

[lewpopp]

Just about 15 minutes ago the pump came on and stayed on until I turned it off. I will turn it back on and time how long it takes to shut off(if it will)

As for the leveling system, it is a "key-on" sustem. I have just acquired the leans over the past month. I will not go under to inspect.

As long as the 2 systems are not connected when the engine is not running, where in the hell does one look.

I just ran the compressor and it dod not shut down so I shut it down.

Tomorrow's another day. Thanks

Man! I just got a call from my doctor(a Greek and I almost hung up on him thinking it was a sales call) and he had the results of my blood test. He called at 10:15 at nite , can you imagine that. I had to makr some major changes in my prescriptions. Hope I make it untiltomorrow.

[Jon Wehrenberg]

Lew...you are dealing with 2 separate unrelated issues. The leans for lack of a better word and aux air system leaks.

I suspect, but do not know if your pump pressure switch is set too high, or if the air at max pump pressure is leaking out at a rate too fast for the pump to keep up with.

The question of where to begin with aux sytem leaks is a good one and should be answered by Marathon owners, especially those who have had experience with your vintage of coach. Each converter has a variety of devices on an aux air system and there are ways to isolate those devices to find leaks.

As to the leans, it is going to be specific to either the front, left rear or right rear, although it is possible for all three separate sections to be leaking if the Norgrens and air bags are old.

Don't worry about the coach however until you get your health and meds under control. The coach will wait.

[truk4u]

Louie,

Hang in there! I would suggest you run the aux compressor and watch the pressure gauge while it's running. Your compressor should have a pressure gauge on it, or look in the steering bay, you WILL find one. Watch it while the compressor runs and see if it's building pressure. If it kind of just hangs there and doesn't build, it could be the compressor itself. If you had an aux air leak that was bad enough that the compressor couldn't keep up, you should be able to hear it.

Like Jon said, forget the suspension for now and concentrate on the air floor slide, toilet (if it's air), air seat, any air pocket doors, generator air bags if you have them and any other air operated gizmos.

I feel sorry for Kathy right now!:D

[mike kerley]

Lew, do you have an air ride drivers seat. They do have a tendency to leak. find the line from the front compartment going up to the seat and turn it off. See if that stops the leak. Ours had a seperate valve and I'll bet you do too.

I hope the med's change helps. Take care of yourself first, the rest is just barely important...

Mike and Karen

[lewpopp]

Thanks guys for all of the suggestions and tips. Yes, I do know that the leans is separate from my present problem

Horrie Mackeral, the Greek Dr finally called in the script at 4 pm and the pharmacists told Kathy that the dose is for 6 days and "tastes like shit". His exact words. I took it like a man and held my nose and it worked.

I have been spending amlpe time at the compartment under the drivers seat so maybe that's the proble,\m. Maybe I should have a beer like the rest of you guys.

The compressor took off again and ran for about 10 minutes today and I shut it down again. I turn it on about an hour later and it pumps up to 90 and shuts down. About once a day that happens.

Several years ago i replaced the front seats and kinked the air supply to the seat. I will check that and perhaps plug it off properly and see if that's the culprit.

I am repeating my self, but it pumps to 90 and leaks down to 67 and holds and services the air needs for most of the day. It came on as we were going to dinner and I waited and it went off in 3 minutes. It used to only take 2 minutes.

[Jon Wehrenberg]

Lew,

This is not a repair in the sense of the word, but it may temporarily ease your concerns.

Reset the cutoff and start pressure points for your compressor. If you do not need 90 PSI, adjust the compressor "off" pressure to 75 or 80. That is going to reduce the load on the compressor.

Then adjust the "on" pressure to 50 or 55 for example, assuming that pressure is sufficient for the systems that require pressure. In other words it appears your leak down rate based on time is less at lower pressure. Until you wish to find the leaks just set the aux compressor on and off settings to maintain a lower system pressure. On my coach I could do the same thing because unless I wanted to level the coach using the aux system air everything else will function at relatively low pressure settings such as the bed lift and pocket doors.

[lewpopp]

Jon, thanks a lot. I expect your idea is the best for now. I haven't taken the time yet to look for the line to the seat that we kinked. Other issues seem to weigh more right now. All the cycles seemed to be normal today.