Aux compressor

Jim Barone · #1 03-06-2008

I want to use an aux compressor to check tire pressure but I don't want to introduce water into the tires. If I introduce compressed air from the the aux compressor into the Schrader valve in the engine compartment, will that compressed air be routed through the air dryer? Thanks, Jim Barone 1991 WBWL fulltiming currently in Tubac Arizona

peteaeonix · #2 03-06-2008

In my coach, the schrader valve for 'shop air' is located right next to the engine-mounted compressor, so it must travel through the wet tank and then the dryer. I'd assume that a '91 would be set up in a similar fashion.

My "aux" compressor is a contractor's type portable unit (kept in a basement compartment). I got a small air filter/dryer device that reduces the amount of water in the compressor output, but it's probably not as dry as the air that comes from the dryer on the coach.

Jim Barone · #3 03-07-2008

Thanks for the input Pete..Jim Barone

RGloverii · #4 03-07-2008

Shortly after purchasing my coach, I asked our local BlueBird dealer (Holland Motorhomes) the exact same question regarding the schrader valve, and was given the same information:

The schrader valve DOES go through the wet tank, and therefore goes through the drying process. My coach came with a factory aux compressor, but when docked at home, I tend to use the schrader valve with my shop air to air up the coach quickly before travels.

peteaeonix · #5 03-07-2008

Since airing tires was mentioned, I guess the second question should be, where is the air-output connection tapped into the onboard air system? Does it come off the dryer or is it off the wet tank? (My air tap is in the street side compartment just ahead of the water/sewer connection compartment.)

I also note that it's dreadfully slow at adding air to the tires. Since the air system is limited to 120 psi and I need 120 psi in the drive axle tires (due to load), it takes near-forever to pump up those tires from the on board system. (Tires that need 95 or so psi aren't so bad.)

Of course, that's why I ended up with a contractor's 150 psi compressor to carry along.

peteaeonix · #6 03-07-2008

Since airing tires was mentioned, I guess the second question should be, where is the air-output connection tapped into the onboard air system? Does it come off the dryer or is it off the wet tank? (My air tap is in the street side compartment just ahead of the water/sewer connection compartment.)

I also note that it's dreadfully slow at adding air to the tires. Since the air system is limited to 120 psi and I need 120 psi in the drive axle tires (due to load), it takes near-forever to pump up those tires from the on board system. (Tires that need 95 or so psi aren't so bad.)

Of course, that's why I ended up with a contractor's 150 psi compressor to carry along.

jwasnewski · #7 03-07-2008

I quickly looked at the complex diagram I have for my coach. It may take some further studying and highlighting. The shop fill goes through the dryer, as does the compressor and the aux air pump. The aux air pump has a check valve to protect back flow. The accessory air appears to be serviced through a junction box for the rear tag axle relay valve. Of course that is air that has presumably been previously passed through the dryer. I get a little condensation out of my service port presumably because of the run from the source to the connection plug. I will send you the diagram if you want it. I will have to scan it in two parts.

peteaeonix · #8 03-09-2008

Leroy,

Thanks for the offer of the diagram -- I'm not quite ready to tackle dealing with that right now. However, it might be nice to post a scan to the files area of the list.