I have a 2001 U320 with 1 slide and will be placing it in storage for several months each winter in Florida without shore power. If you turn off the 12v compressor so that it does not run down the batteries, what keeps the slide bladder inflated?
When the 12v compressor is turned off, I do not think anything will keep the slide bladder inflated while MH is in storage. At least that's the way it works on my 2002 U320.
I turn the compressor off for weeks at a time, the seal never deflates. I also dump the air bags letting it sit on the bottom, when need to take a trip, I just reconnect the compressor, let it come up to pressure so the seal will deflate in order to get the slide in. WHen get back and put back in garage, disconnect the compressor until next trip.
Cheers
Dave M
I've left my compressor off for 4 weeks and the bladder didn't deflate very much. Definetly want to turn the compress or off though! I am close to storage so I would run out, start the generator turn stuff on, leave for a couple of hours and come back to turn the generator off. Now I'm in an inside storage with 30 amps though :)
Not advisable to leave the coach dormnant for that long without exercise every 4 to 6 weeks. This entails running a 30 mile total each 4 - 6 week period. At each exercise period you basically get the coach ready for a trip to make sure everything stays running, tire presssures are maintained, bladders are pressurized, A/C's seals are lubricated (including dash A/C), aquahot, transmission, diesel engine, genset is exercised as well...so on and so forth.
Would love to take it for a run in winter but with all the salt here in the Chicago area ( No, Virginia, that's not snow on the road but salt) I don't want it eating the coach. As the storage is heated and I spin the engine over with the fuel off to get oil around the engine before starting and 10 miles of gentle operation it's not such a big deal. My boat on the other hand has endured 40 years of winters sitting out by Lake Michigan under a tarp. Starts right up in the spring and still runs like a champ on it's original engine and trans. All it gets is Stabil in the fuel and an affectionate pat!
I have seen equipment left for years at a time sitting and rusting that started right up and kept going with just a jump. Not recommended for a coach but it's amazing the abuse some things can take.
Keith
Thanks for all the great feedback. So I have not let the coach sit long enough yet to see if the bladder will deflate but I'll bet as long as there is at least 12 psi in the main tanks it will be fine. The bladder will inflate and deflate without the compressor as long as there is sufficient air in the main tanks which appear to be tied into the HWH tank. Is this configuration unusual?
I had disconnected the compressor a few months ago and when I needed to leave, had to retract the slide, it did not seem to pull the seal back until I reconnected the compressor and let if build pressure, then the seal retracted. Maybe I am clueless, but I felt the DC compressor had to have pressure to operate the vaccum side of the seal.
Would like to know for sure.
Dave M
Dave, my dc compressor doesn't work right now. If I start the coach and let the pressure build, the slide seal inflates or deflates normally.
On our 2003 I was told by James Triana that starting the engine should not fill the lines to the bladder as shown in the diagram below. I always thought it did since I saw my air gauge going up when I ran the engine.
Only the Aux compressor feeds the line to the bladder UNLESS the check valve on line 57 is bleeding thru which is one of the reasons I had to replace my check valves. What did you do to your coach today. (http://www.foreforums.com/index.php?topic=13754.msg113229#msg113229)
I am finding all my check valves are corroded and are being replaced due to air leaks over the years.
The 12v compressor will also build pressure in the main tanks on my coach. I suspect one or more check valves are not functioning properly and/or someone has modified the system. I have only had this coach since November and am still crawling up the learning curve. We need to have an air system "busted knuckle" rally to troubleshoot and fix stuff like this - more fun to do with others than by yourself, at least that's what worked well for me when I used to play with antique cars.
That would mean the check valves on the air tanks identified on the diagram below are bleeding thru.
You can see the corrosion on mine in the photos and replacement part numbers What did you do to your coach today. (http://www.foreforums.com/index.php?topic=13754.msg113229#msg113229)
I decided to finally get serious about fixing all the air leak issues on my coach and fully understanding how every aspect of it works. Working with the diagram I have been under the coach along with a mechanic from Colton Truck following every line because it has not been exactly like the diagram said and I was chasing my tail. James T sent me other air diagrams that might match mine but I found mine was a mixture of both diagrams. I think because it was the pre production model changes were tried out that maybe were not fully documented. :(
Seems we are all having issues on understanding how the air system all works together and finding the air leaks. I am working on documenting my findings of how it all works in english and expanding on the great information from Jerry Whitaker in this thread Our leveling system problem (http://www.foreforums.com/index.php?topic=12423.msg70631#msg70631) but it is turning out to be quite a task since it involves several systems and I don't want it to be to technical.
The same with my electric diagram. I had to trace each wire and relabel some so I would have a good starting point.
Barry, thanks for posting the air line diagram. Look forward to the air system explanation you're planning.
I can see from the diagram how a bad check valve in 57 could let the brake tanks inflate the slide seal. I can't see how this would affect the vacuum generator - didn't even know we have a vacuum generator. Do know the slide seal won't deflate with my dead 12v compressor unless I start the coach and fill the tanks.
Vacuum generators use compressed air to generate a vacuum via a venturi - I used them to build home made one-man brake bleeders for antique car brake systems.
http://www.exair.com/en-US/Primary%20Navigation/Products/Vacuum%20Generators/Pages/How%20the%20E-Vac%20Works.aspx (http://www.exair.com/en-US/Primary%20Navigation/Products/Vacuum%20Generators/Pages/How%20the%20E-Vac%20Works.aspx)
Jeff - Thanks for the link. Doubt if I actually understand vacuum generators but if Foretravels use this venturi type, seems compressed air is what drives them.
This takes me back to the schematic Barry posted earlier. Looks like line 75 feeds the s/o air seal and the vacuum generator. Line 75, line 76, and line 57 look like they come together but not sure what actually connects to what. Looks like the 12v compressor feeds line 57 and line 75, but what does line 76 do? Is 76 from the wet tank or to the wet tank? If it's from the wet tank, looks like it must feed 75 and/or 57.
Too many questions - looking forward to Barry's plan to describe how all this works.
The way I read the drawing that would make me happy if #57 and #76 only allowed air pressure to not enter the chassis air system, #75 only allows air to the slide seal tank.
The engine driven compressor fills the wet tank and everything beyound it, I would not want the little DC compressor trying to keep the entire air system pumped up, just keep the slide seal inflated.
Looking at my air schematic shows two #57 check valves in series.
Since my slide seal does not appear to leak, the very slow leak(s) would have to be either bad check valves and/or the leveling system/air bags etc. Why I have no problem turning the pump off and setting the coach in the down position.
SO the #57's, #27's,#50, #28's, #55's
My Drawing is B-2193
We all need a clear head looking at this stuff. And I sure could be off track. ;D
Dave M
On mine
The 2 check valves you are seeing.
One is on 57 only (large one) & the other is a check valve for all 3 lines 57, 75, & 76. It is a very small nipple check valve.
I would like t install a solenoid on the 57 line near the DC compressor, but turning it off works too in my situation. :o
Dave M
Talked with James Triana. He says my coach doesn't have line 76. Line 76 is used to let the 12v compressor air up the main system. In my case, Barry must be correct, have bad check valve(s) in addition to bad compressor.
I don't have line #76 either so it's failed check valves in my system. I guess the good news is I have the option of using the 12v compressor or the big dog compressor to air up the system and manage the slide seal. Suppose I did nothing to fix this problem? - I guess the down side is I cannot isolate the slide sub-system from suspension/step well/etc. leaks. Not an issue when the leaks are small and the coach is driven often but extended storage with the 12v compressor off (which is what I do) may be problematic. Other than getting out my divining stick and soap suds, are there any other options?