Air line from Compressor to drier

robertglines1 · October 05, 2013, 02:32:30 PM

Last connection for my project.. Prevost has Teflon line with stainless steel braid at least 11 ft long before Air drier. I want to relocate air drier to engine compartment for convenience. Any problem with that? What should I use for Supply line? The reason I was told Teflon was high temperature of discharge air from compressor. One area a day is my goal to button up. Bob

Utahclaimjumper · October 05, 2013, 02:39:02 PM

I have found that the line from the compressor to the dryer must be at least 6 feet long and mounted to achieve a continuous downward angle to the dryer.>>>Dan ( American Coach uses Aeroquip aircraft stainless.)

luvrbus · October 05, 2013, 03:52:05 PM

Bob,Prevost mounts the AD-9 12 ft from the compressor ( 10 ft min) the AD-9 needs to be mounted away from any heat source, yours if a Prevost setup will probably have the turbo cutoff valve on the AD-9 to keep from drawing the boost away from the engine and prevent the nice little codes from flashing

We were told in the Bendix school the longer the run to the dryer up to 16 ft the better it was on the dryer it creates a cooling affect before the dryer

good luck

robertglines1 · October 05, 2013, 04:42:34 PM

Now that makes sense. I can understand that! The drier can go rite back where it was in front of the wet tank. With the long supply line. Was just trying to make my re-plumbing and future maintenance job easier. I know why not to fool with it now! I sure hope others learn something from my questions and I'm not the only one that wonders why the powers to be do things like they do. I do remember things when they are explained to me. I did notice the air intake for compressor was thru intake manifold and wondered how that would affect boost sensor. Just figured someone was smarted than I when they allowed for that or compressor need was a less than1% of total flow. Life is good. Thanks Bob

Jon · October 06, 2013, 03:38:19 AM

It's all about cooling Robert. Hot air can hold a lot of moisture so to increase the effectiveness of the air dryer and remove moisture more effectively if the heated compressed air can be allowed to cool the dryer will be able to capture more moisture. Nothing says you cannot put it in a bay.

As far as service, I only do mine when I am under there for other reasons also, such as when I grease it so locating it beneath the coach doesn't pose a problem. I question the need to always run the line downhill. On my 97 the dryer was mounted high up on the frame, passenger side above the height of the compressor. I never had moisture in any of my air system with the exception of a spoon full in the wet tank from time to time.

Zeroclearance · October 06, 2013, 08:36:31 AM

Bob, on my H3 the air line out of the compressor is about 3 feet long. It is made by Parker Teflon/braided. It is connected to a solid line (it looks like stainless) that runs forward to the Haldex air dryer. The dryer is mounted ahead of the driver side drive wheel at the same level as the wet tank. Front the dryer to the wet tank it's about 2 feet.

bevans6 · October 06, 2013, 10:02:21 AM

The MCI's have a "ping tank" or discharge muffler on the fire wall about three feet from the compressor. It's nothing more than a piece of 1 1/2" iron pipe capped at both ends with an input down low, output up high and a drain at the bottom. Smooths out the compression hits from the compressor and gives a place for the oil and water to condense. Teflon flex line to the ping tank, hard line from there forward to the air dryer.

Brian

Boomer · October 06, 2013, 11:05:03 AM

Eagles have a copper cooling loop on the discharge line to take some of the heat away before the drier. This is a good space saving option if the drier has to be installed near the compressor.

Oonrahnjay · October 07, 2013, 09:39:40 AM

Quote from: Boomer on October 06, 2013, 11:05:03 AM
Eagles have a copper cooling loop on the discharge line to take some of the heat away before the drier. This is a good space saving option if the drier has to be installed near the compressor.

My bus has "accordion pleat" cooling fins on the metal pipe for about 8 feet of its run; there are a number of ways to make this work but the big thing is to cool that compressed charge down (as others have said). While you're at it, pull the connector at the compressor and look for carbon in the line; they sometime will get coated with oil and then the heat will carbonize the oil. It can build up to be a significant constriction.