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Topic: Aux Compressor Stumped ? (Read 515 times) previous topic - next topic

Aux Compressor Stumped ?

We just got back from a trip and everything on the Aux. Compressor and Leveling worked fine. 
Parked the Coach in the garage, set on Auto-Level and after a couple of days, when the Aux. Compressor started, once it got up to pressure, it would not shut off. It would just cycle on-off-on-off-on-off-on and continue until I manually shut it off.
I assumed it was the pressure switch and ordered this one:
Square D by Schneider Electric 9013FHG2J27 Air-Compressor Pressure Switch,...
I replaced it (that's the new one installed in the picture without the cover. but still have the same problem.
Also, when working on it, I saw that the wire with the tape labeled Aux. Comp. Solenoid was just rolled up and tie wrapped without connecting to anything.  What is this for? (Red Arrow) I thought that was where the air line that controls the slide bladder connected to but wasn't sure.
The system has been working fine for years as wired until this problem popped up.

Is there any other piece that would make the compressor shut off once it achieved pressure ?  I am stumped.

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Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad

Re: Aux Compressor Stumped ?

Reply #1 –
There should be a check valve.
If you haven't changed it yet, it might have rust inside preventing the o-ring from seating.

Cheap part.
1991 Grand Villa U300

Re: Aux Compressor Stumped ?

Reply #2 –
Try the compressor manufacturers' website for a wiring schematic.
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Aux Compressor Stumped ?

Reply #3 –
So the red wire I believe commands the compressor on when leveling. Any time you push a manual valve it raises and runs.
So you have a leak somewhere.
I would turn the HWH shut off valve to the slide and air awning to isolate. If it shuts compressor off you know your compressor is correct. Then one at a time add systems back in till you have a resolution. Also isolate your leveling to see if it has leaks. Your arrow is pointing to the compressor tank solenoid  which isolate the tank during level commands
Scott

Re: Aux Compressor Stumped ?

Reply #4 –
Scott,
Is there a reason that the wire with the tape label on it isn't going to anything?  Of the two wires coming out of that solenoid, one goes to a ground screw and the one with the label was just tie wrapped in a bundle.
I'm leaning toward replacing the power relay that controls the compressor. Is it possible that it could be stuck?  It almost seems like the pressure switch is working properly and sending signal to that relay, but the relay isn't reacting, thus the pressure switch just keeps opening and closing continually.

Everything else seem okay.
Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad

Re: Aux Compressor Stumped ?

Reply #5 –
Would anyone happen to have a part number for the power relay that controls the Aux. Compressor ?
Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad

Re: Aux Compressor Stumped ?

Reply #6 –
I think I need to better describe the issue.  It's not that the pressure is leaking down and the compressor runs to build pressure, then stops, looses pressure and starts up again, then keeps repeating.
It runs, builds pressure in the tank, then when gets to the shut off pressure, the pressure switch reacts, but the pressure switch contacts just keep opening and closing and the compressor keeps running.  The tank maintains pressure, it is not leaking down.
That's where I thought maybe the pressure switch sent a signal to the compressor relay/solenoid to shut down, but maybe it is stuck.

Hope that describes my problem better.
Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad
 

Re: Aux Compressor Stumped ?

Reply #7 –
Quote from: MarkC –
Would anyone happen to have a part number for the power relay that controls the Aux. Compressor ?

I just bought this one from Ebay.  Same part number as the relay that was in my coach and was bad. 

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If the link doesn't work, search for: White Rodgers Solenoid For 12V Universal 120-105111-5
2000 U320 4010