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Topic: Need Help With Air System (Read 538 times) previous topic - next topic

Need Help With Air System

I'm trying to figure out why my auxiliary compressor runs every two hours since rebuild.

From looking at the air schematic and inside the electronics bay I don't see any check valve between the auxiliary compressor,
the wet tank, slideout seal tank and the six packs.  Looking at the plumbing it seems that everything after the last filter bowl (that's mounted in front of the compressor motor) is tied together along with the pressure switch.  When the compressor shuts off the purge valve opens and relieves the pressure everywhere. 

If that's so, then how does the pressure switch operate to turn the compressor on?

Re: Need Help With Air System

Reply #1 –
Quote from: Travelin' Man –
I'm trying to figure out why my auxiliary compressor runs every two hours since rebuild.

From looking at the air schematic and inside the electronics bay I don't see any check valve between the auxiliary compressor,
the wet tank, slideout seal tank and the six packs. 

Can you post/upload your air schematic?  IIRC they are marked in several different ways on the air schematic.  Possibly little arrows in rectangles, rectangles with sizes next to them, etc.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Need Help With Air System

Reply #3 –
My HWH compressor has a check valve. It doesn't even look like one. I had to take it apart to find it. It's in one of the last brass fittings before the air line out.
Chris and Tammy White  CDA Idaho
Previous owners 1997 U295 36' 3126 Cat 300 HP Build # 4998
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Need Help With Air System

Reply #4 –
T-Man,

Here are a couple of resources that may help.  On drawing MP79071A-B the aux compressor is the circle in the lower left hand quadrant.  It's unlabeled but the output of the aux comp feeds the filter and desiccant dryer.  Check valves are noted as symbol <O

Mark
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: Need Help With Air System

Reply #5 –
T-Man - does your coach have any slide outs?

EDIT: Never mind I read above in your original post that you do have slide out(s). 

If your coach is like mine, there is a 1/4" ball valve on the supply side of the slide out air manifold.  See the blue handle in the photo. Your OEM valve may be brass with a black handle.  If you close that valve and the leak stops then you'll know that the air is escaping downstream of that valve.  Speaking of that valve, I've been told it is a common failure item due to o-ring wear.  Some choose to replace the ball valve and some to repair it.  I replaced it with a new valve from Amazon. 

If the leak is downstream of the slide out manifold supply valve, the air pressure regulator for each slide out is a known leak area.  It is shown in the attached drawing.  I've had to replace one of my two so far and I suspect the other one is leaking a little.  You can unscrew the top of the regulator and clean the seat and the rubber membrane.  Might help.  There's a port or hole in the side wall of the upper portion of the regulator.  In my short experience that hole is where the air escapes when the seal inside the regulator is leaking.

Mark
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971