[Archived]

If the air dryer is maintained you will never get moisture in any of your tanks.

[Gerard]

Makes sense…Thank you Jon!

[Archived]

One of the previous owners of our bus had Prevost Jacksonville install automatic drains on the air tanks.

Our bus also had a good documented history of air dryer service. I’m on a two year replacement cycle for the air dryer.

We have never had moisture when manually draining the tanks.

[Gerard]

Thank you Les – great to know!

[Archived]

OK, just to be clear and to not allow anyone to be mislead servicing the chassis air dryer will not protect the pneumatic system entirely.

Any time we are parked for a length of time and the aux compressor cycles to keep slide seals inflated or to allow operation of converter installed air operated devices moisture is introduced. I will use a broad brush stroke and say I have been underwhelmed by every converter attempt to keep moisture out of the coach air system so my message is the aux compressor is a likely source of moisture introduction to the accessory part of the coach air system.

I’m not sure I would be comfortable with an automatic drain on any of the coach tanks, but until or unless something can be added to the coach to capture air from the aux compressor and trap the moisture it is going to be a better way of protecting the coach air systems.

If enough moisture is added to the accessory system such as via the aux compressor the impact can be very serious. not only will various ping tanks and air bags trap moisture and retain it, but the presence of moisture is going to damage Norgren valves, protection valves, ride height valves and all the converter installed pneumatic devices. The cost in dollars to fix moisture damage will exceed the amount of dollars of dues money Tom has withheld from me.

[AL]

I try my best to minimize moisture in the aux tank. When I’m parked in the storage garage, I open the driver’s bay and release all the air from the aux. compressor.

I leave the coach at ride height and it takes about a month for it to slowly lower (seems even) but I’ve never seen it, after two months, reach the stops.

I also empty the ice-maker and turn off the water pump. Weekly, I flush the toilets and run water through the shower pump.

The 2016 Marathon parked across from me is used less often and their coach is definitely on the stops as the flaps are touching the concrete.

Safe travels,

Mark

[glen]

We purchased our bus in Stuart, Florida and headed straight up the east coast so have not yet had it home and up on my 2 x 12 wooden ramps that will raise it 6″ in order to even see the auxiliary compressor. I did ask, and was shown, three valves located in the bay immediately below the driver seat that can be opened to drain air from the auxiliary compressor tank, and I have opened them at each stop along the way and no moisture has been present.

Is there anything more to do or, better yet, that can be added to better protect the entire system from moisture introduced from the auxiliary compressor? I have never had an auxiliary compressor, yet know my pancake compressor at home produces significant moisture and must be drained often.

[Archived]

I will not attempt to suggest a specific best way to trap moisture generated by an aux compressor. But conceptually the introduction of moisture begins as humid air drawn in and compressed by the aux compressor. It is heated as it is being compressed so the moisture is still a gas (vapor).

The only way to trap that moisture is to allow the compressed air to cool, and the vapor to condense.

So downstream from the compressor is the best place to allow the accumulation of that condensed water vapor and it can be a dryer, such as a small version of the chassis dryer, it can be a water trap, it can be a tank or any device whose purpose it to retain moisture and only allow dry air to proceed downstream.

If in doubt or uncomfortable about how the coach aux system is protected against moisture do some internet research, check with folks like ETLC or Tradewinds about adding a device, or see what others have done. Each conversion may have a different approach due to how the accessory system is set up.

[Archived]

Our accessory air compressor was 14 years old and beginning to be noisy. I sourced a California Air Tools ultra quiet oil free air compressor that fits nicely. To help with the moisture issue, I bought a Norgren filter/dryer. ETLC installed both. I’ve not had any moisture problems and with frequent draining of tanks, filter/dryers, and dryer service every two years it should stay that way.

[Tim]

Any moisture trap, tank or dryer for the aux compressor has to be located far enough from the aux compressor so the entrained vapor condenses out as the air is cooled. So if installing something as Les has done make sure it is far enough from the compressor for air to cool.

[Deleted User]

Jon, that was certainly a concern.

The way the accessory air system is plumbed is different from the main air system, driven by the engine. The main air system has the dryer a distance from the compressor and finally the air tanks.

The accessory air system has the compressor, then air tank. The hot, moist air is stored in the compressor’s air tank where it cools and most of the moisture collects at the bottom of the tank. When accessory air is needed, the cool air from the tank, in my arrangement, goes through the new Norgren air filter/dryer and then to the accessory supplied needs, normally the driver’s air seat and generator air bags on our Country Coach.

When parked the accessory air can also supply the HWH system (if left active) and that can be an issue if moist air gets in to that portion of the bus system.

Where to put the air dryer for the accessory system is certainly important. Just realize that space is limited and the system is indeed different from the main air system. Having an air drying device on the accessory system is definitely an improvement.

[glen]

Jeff and Sandy,

When I was in Stuart in summer of 2016, your coach was there having service too. I noticed that yours had the front windows tinted and the owner mentioned how nice it was to prevent glare and kept the front a little cooler.

So, I had ours done too (front windows and sides). I love it. On sunny days I will wear sun glasses but the tint does keep the coach cooler and it has much less glare.

Did you keep the tint?

Mark

[Rudy]

Mark, I’m guessing you tinted the top part of the front windshields???

[Linda]

Les, on the chassis Prevost has a run of about 15 feet between the compressor and dryer, and then downstream from the dryer with a run of about 3 feet is the “wet” tank. That way the chassis has 2 chances to prevent moisture from migrating into the braking and accessory systems.

If your aux compressor has limited space downstream to a tank or water trap or dryer you can accelerate the condensation process by using a coil of copper tubing between the aux compressor and the next component in line, such as the tank. The problem I see with a lot of accessory systems is some feed aux compressed air into the chassis accessory air tank so it becomes the moisture trap, or if the converter installed some means of trapping moisture before it reached the Prevost tank it was not convenient or easy or in some cases possible for an owner to drain aux compressed air moisture. Some converter installed traps or devices to purge moisture don’t even do a good job and unfortunately some owners do not know that until moisture accumulates and damages parts of the pneumatic system.

[Ronald]

Les, no, I had both front windshields tinted top to bottom including the driver’s window and the window in the door.

The upper side windows are already dark.

It also gives us a little more privacy in RV parks on sunny days if I don’t have the mesh screens lowered. It’s hard to tell on the inside that there is much tinting until I lower the driver’s window.

I don’t recall the percentage, maybe 40%? If we are ever in the same place, like we were at ETLC last October, I’ll show you.

Safe travels,

Mark

Here are the ‘after tinting’ pics. The one with the driver window, you can see the difference looking through the window to the fabric on the pillar by the exit door. The top 1/4 inch of the little window is not tinted so that it can slide into the grove.