View Full Version : Norgren Auto drain / Fogger ?

08-29-2017, 02:15 PM
While looking at the Norgren site and valves and all the links associated with them. I run across this Auto Drain water separating unit with an auto fog deal on it that disperses the correct fogging oil to the Norgren valves. Is this some new technology ? Are they placed on the new coach's ? Auxiliary air maybe ? Under the directions for the valves it says USE A FILTER AND LUBRICATOR.
So, are they new technology that has not caught on yet ? Or are they not applicable to our prevost pneumatic systems ?


08-29-2017, 04:07 PM
Prevost does not put oil foggers of any kind on any coach. This is more of an industrial concern, where rapid valve cycling can occur. With the low cycle rate of any valve on a motorcoach, it really isn't something that is necessary. The only auto-drain installed is the one on the main descicant air dryer in the drive axle area. Prevost has never to my knowledge put an auto draining water separator in the chassis system. Very few converters even do on their aux air system. We are in Florida, however, and have always put auto-draining moisture separators on our aux air system, and also suggest that to our service customers of all conversion brands as a retrofit. Most of them agree.

08-29-2017, 04:53 PM
I guess I could see a fogger being installed in the aux system, but in line with what Ben said, I wonder if there's enough air movement for the fog to make it to the valves. I also wonder if accumulation of oil in the air bags, slide seals and other systems would be a good thing. The bottom line from my perspective is that Prevost doesn't install them, so they must have a reason why.

As for auto draining filters, Marathon installs them in their aux system. My aux system, which I installed because Hoffman doesn't install an aux air system, rarely accumulates water. I only use my aux compressor when parked and it only supplies air to the Prevost slide seals and generator bags.

08-29-2017, 08:46 PM
Talked to Norgren today. They said " We have had them used on many commercial vehicle applications for the air systems in the past. Going to do some more reading and research on them. I definitely need a better filter separator on My aux air.

Joe Camper
08-29-2017, 09:49 PM
I think that is something worth looking into. Every time u turn the key on and off a signal of air is going to one end of the norgren or the other Gill, I'm pretty sure it would be getting there. Residue accumulating in the bags, not if u have ping tanks attached to the bags. It will accumulate there. Thats 97 and newer. Even chassis without ping tanks, I'm hard pressed to find a adverse effect for slight oil residue in the bags and very curious to learn if for whatever reason it wasn't good.

The weak points on the norgren is first, a very tiny pinhole that goes into the end of the bore at the point where the end caps screw into the main body. On a 3 position there is one pinhole on both ends on a 2 position there is on 1 end. U have to look real close to see them.

Another bad thing about the norgren that kills them is they use metal screws to hold the aluminum end caps. When u cant get them off without cutting the heads off what u see on the bore of the housing once u do is electrolysis bigtime. A fogger couldn't prevent that but defiantly delay it.

But the pinholes, they r there to vent the air at the end of the spool because if u did not the spool would be creating compression pushing 1 way and a vacuum on the backside and would take extreemly high pressures to overcome.

That's what kills the norgren most often IMHO. Moisture and dust gets in right there. That fogger may really aid in this design. It's not cycled frequently but they r in an extreme environment at the back end of the bus down under.

Then there's all the air pocket door, bed lift, step slide ect ect cylinders that I'm sure would benifit along with all their micro mac controls.

This fogger should be looked into and if found to be suitable and then should be tested, it could potentially prolong the life of the norgen not to mention the possible benifit all the other brake relays ect ect.

Very interesting. Great thread Rocky.

Gill if prevo doesnt install them they must have a reason.

U r taunting me with that comment.

08-30-2017, 08:21 AM

There are numerous self discharging water separators designed for air systems. If you want to take air filtering to the extreme, look at the air systems for automotive painting. They filter, separate water, and have dryers. They aren't high volume, but more than ample to handle aux air requirements.

If aux air compressor cycling can be limited, the production of water will be reduced. It's not too difficult to to limit aux air distribution to just those systems that require it if you don't have an auto leveling system our don't use the auto leveling system after you are parked. My aux air only supplies air to my slide seals and generator bags.

Aux air compressors should not be needed when the engine is running. I know some converters don't keep Prevost aux air tied to converter aux air. This really makes little sense. At the very least they should install a check valve that allows Prevost aux air flow to the converter aux needs so when the engine is running the converter's aux air pump can be turned off.

Some converters used 12V aux compressors. These DC powered compressors tend to run hotter than AC powered compressors. More heat means the potential for more water.

Joe Camper
08-30-2017, 10:59 AM
Ditto to your entire post Gill however I still like the idea of lubricating the norgren with norgrens own system. I got a seeking suspicion that could be a really good thing.

08-30-2017, 12:46 PM
The norgren website says that if the valves are properly lubricated ( Via the fogger ) the valves will last one million cycles. And it gives instructions of the location that the fogger needs to be placed. Downstream from the air dryer and as close to the valves as possible. And is very specific on what type of oil to use that will not damage the O-rings. I think the amount of oil introduced into the system can also be controlled. If this oil will not damage the fragile O rings , I do not think it would harm the air bags. Our coach's probably never get over tens of thousands valve cycles maybe for the life of the coach. Who needs a prevost valve to last one million cycles ? And they should last up to ten years without the fogger if the pneumatic system is properly maintained. So from prevost's position they probably think 10 years life is acceptable lifespan. And really it is for a new vehicle. After I started reading and looking into them. I thought that having almost completely rebuilt my pneumatic system. It would cost Me maybe 12-1500.00 more to add 2-3 of these and greatly reduce my chances of having any future problems on My forever coach. With Norgren telling Me that they have sold several that were used on commercial vehicle air systems. I still have some questions. Who uses them , How long have they been using them and was there any significant improvement ? Or any adverse affects to the air bags or brake chambers ?

With Your background in communications You probably are familiar with this old technology. For those of You that have seen a air tank chained to a telephone pole and wondered what it was for. The following is for You.
I am familiar with some air filtering systems that produce air that has 0% Humidity. Not in how they work , but in what they do. I have a utility truck that is used to work on underground pressurized telephone cable. It has an onboard compressor with air dryer that is designed to safely put air pressure on pulp insulated copper cable. Paper insulated twisted pair huge cables. That cannot get wet. Back in the day when there was a wreck or a backhoe dug up one of these cables. It would take weeks sometimes to get them repaired. There was no color code other than tip and ring colors in each 100 pair group. If it was severed , Each and every pair would have to be toned and identified from each end. 2700 pair cable cut , The news crews were out on it. Most of this old cable has a lead sheath and was placed in manholes and duct systems. And would stay submerged in water. The telephone central offices had compressors that kept the miles and miles of cable pressurized. Whenever there had to be some activity or maintenance done anywhere along that route. You would have to buffer or add air to the side of the cable that no longer had a feed from the CO. So you could use this truck to add air. And or add a Nitrogen bottle on a pole with regulator to supply air from the field end.
I hope to dissect and compare My UG truck compressor drying unit and I might just learn something that I can apply to My beloved prevost system. Yes ..... I have a lot of time on My hands. But I loves My ole Prevost !

08-30-2017, 05:12 PM

My comment about the bags is that oil would go into them but would not likely come out. At least I don't think so given the air fitting is on top of the bag. I have no idea how much oil would accumulate in the bag, if any.

There's another way to oil the system. Just use an old Junair compressor ;-) I'm surprised how much oil those things puke when they get old.

Keep us posted. I'm sure many will want to know the results.

08-31-2017, 01:44 PM
Gil, I don't advise that as the Jun-air oil is acidic and tends to degrade the seals in valves and cylinders quite quickly. The oil they use in the fogging system is different and not acidic, and does not eat the rubber o-rings and quick-connect fittings like the Jun-air oil does. I figure you already know that but wanted to clarify for everyone else on here.

09-01-2017, 08:17 AM
I was just kidding about using a Junair as a fogger. Junair owners should keep an eye on it's filter. Once they begin to puke oil it can be a lot of oil.

Joe Camper
09-01-2017, 02:10 PM
I think they make great small boat anchors.