I am having an issue with my Air system, not sure what has caused it. It has been dumping Air every now and then but today it got worse. It dump the air from the valve near the compressor and then the compressor kick in to add air back in when it reaches what I think it's set to it shuts off. The problem is at that point the valve dumps the air and it starts the process again, never stops. I pulled the fuse to the pump to stop the cycling but don't know what to do to troubleshoot the problem. Is it a electronic glitch telling it to dump all the air or a bad valve which doesn't sound logical to be the problem.
Just put the fuse back in and it ran what I think is okay, but it raises another question, how long should it take for the system to go from 80 psi to 100 which seems to be the cut off point. Took mine 7 minutes to get there. Then the compressor turned off and dumped the air in the line. So when not running it shows no pressure and when it turns on it gets to 80 psi in about 30 seconds. Is that normal?
Do you mean the normally open solenoid valve on the bottom of the condensate bowl? If so, does it close/seal at all while the compressor is running or does it continuously leak/exhaust air and doesn't ever seal?
It should close while the compressor is running and open to depressurize when the compressor stops.
If what you're seeing is a frequent running of the aux compressor with proper cycling of the "pop off" solenoid, and pulling the fuse stops it, that's usually the sign of a leak in the slide bladder "plumbing" or the bladder itself. First place to check for a leak (if you don't hear one at a slide bladder) is the plastic valve handles for the valves on the slide manifolds (unless someone has replaced them with ball valves already).
R&R of the NO solenoid valve HWH Solenoid Valve Rebuild (https://www.irvblog.com/foretravel%20projects/HWH-Solenoid-Valve-Rebuild/)
Solenoid valve itself is HWH part RAP6354 compressor "cycling" every two minutes (https://www.foreforums.com/index.php?topic=32936.msg296660#msg296660) FOT parts will have this in stock if it is the problem and you don't want to rebuild the old one right now (we used to carry a spare for quick swap-out)
Pic of valves on slide manifolds (after replacement; the original had black plastic handles) followed by pic of NO "pop off" solenoid valve.
Are you talking about the pop off valve?
When pressure gets to high it opens dumping air.
Can you take a picture of what is releasing air?
It is the valve Michelle has in the second picture shows the valve that dumps. I appreciate the replies. I'm thinking Michelle's reply is on the money, I will be checking further on that. But my last question I'm still worried about is it taking 6 minutes or more to get the pressure from 80 to 100 psi, seems very long to me. I guess it could be normal just don't know.
If that solenoid valve is leaking, it's making it more difficult to build pressure. That valve closes so the aux compressor can build pressure. If it's not fully closed, part of the compressed air is going into the system but some is leaking out.
That valve SHOULD dump when the aux compressor finishes its job and shuts off. If it's leaking WHILE the aux compressor is running, the valve is the issue. If it's closing like it should, but the aux compressor is cycling often, there's a leak somewhere (or possibly the pressure switch isn't working properly)
I can't hear or feel air coming out of the valve until it shuts off, wondering if the compressor is wearing out or not
Could still be a leak, but the aux compressor does have rebuild kits
HWH Pump Rebuild (https://www.irvblog.com/foretravel%20projects/HWH-Pump-Rebuild/)
You are a wealth of knowledge Michelle, much appreciated
If it's the pressure switch, Dan's got some posts with good info and links to prior good discussions:
Pressure Switch and coach leveling (https://www.foreforums.com/index.php?topic=45896.msg466546#msg466546)
Oh, and one more thing to check/ask about:
Is the "air tank" rocker switch by the driver's elbow on? Keep it off. It links the main tanks to the aux compressor (which isn't capable of maintaining them). Note this switch was introduced in the 2002/2003 timeframe. Older coaches won't have it. It was added as a "campground courtesy" feature so folks leaving early could start airing up without running the coach engine and disturbing neighbors.
If the switch is off, next time the compressor starts running, turn the ignition key just until you can watch the A and B pressures on the Driver Info Center (don't start the coach). If the tank pressures increase with the aux compressor but that switch is off, the solenoid valve it operates is leaking through. The aux compressor trying to fill the A & B tanks can cause long run times.
There's also at least one check valve in that line as well that can fail. Here is a redrawn air schematic for a 2003 and newer U320 that Barry Brideau made:
Yes, switch off and pressure on both tank increase and pump runs until they reach 86 psi
Sounds like a leaking air tank switch solenoid valve (and possibly check valves). I'll dig in my parts receipts PDFs for the p/n's...
Some here: Leaning Coach, Air Check Valves (https://www.foreforums.com/index.php?topic=16330.msg104082#msg104082)
check valve to protect the aux compressor (RN13526BR)
Solenoid p/n appears to be RAP91775, but double-check with FOT parts.
Thanks again, I will have to see where it is located to see if I can reach it without being a contortionist. Getting to old for that.
Should be on/plumbed to the aux compressor, line #76
Air Tank Switch (https://www.foreforums.com/index.php?topic=32156.msg286692#msg286692)
Air Tank Switch - ? (https://www.foreforums.com/index.php?topic=28412.msg236967#msg236967)
Aux 12 volt compressor compartment "thumping" sound (actually air unloader) (https://www.foreforums.com/index.php?topic=34259.msg315503#msg315503)
Aux pump turning on for no reason? (https://www.foreforums.com/index.php?topic=44581.msg451713#msg451713)