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03 U320 slides

Hi all,

Getting ready to head out to the mountains today and have being witnessing unusual slide operation over the past few weeks.

Heads up: I have not had a chance to dig into the HWH manual yet

Coach on shore power
Ignition on engine off
2 year old chassis batteries
2 month old house batteries
Operating wardrobe or living room slide
Turn slide control on
Almost always the aux compressor does NOT run
Living room slide controller flashes yellow then dark then flashes then solid
Wardrobe slide lights operate as they should
I wait 2 minutes to make sure vacuum is pulled
Then visually inspect seal gap from exterior and have 1/4 inch gap all around
Push extend button and slide either stays put or will move out a couple inches
Repeat above process multiple times with same result
I will test again today but this seems to only happen when extending the slides NOT retracting

So I do not have a air gauge on my line to the aux tank but plan to add that next week. I will also add vacuum/pressure gauges to the slide manifolds as well

Now when I run the engine and after a couple of attempts I can extend the slides consistently

In my mind the Hydro pump is not getting proper voltage or the ground is bad but will gladly take any and all advice on this.

Before the above issue appeared I had noticed that when I operated the slide controllers the compressor would not engage on its own when vacuum was needed. I would raise one end of the coach to get it to kick in.  Seems I may have multiple problems.

Thanks in advance for help on this.

2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: 03 U320 slides

Reply #1 –
Are you plugged in?  Batteries could be dead even though new

Re: 03 U320 slides

Reply #2 –
Personally, I always have the engine running when extending or retracting the slide.  Better results and no issues!
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: 03 U320 slides

Reply #3 –
When you push the button to extend and you say the slide moves a few inches and stops, do you still hear the hydraulic pump motor running?  Is the PUMP ON light still lit?
Keith
2003 U320 38' #6197

Re: 03 U320 slides

Reply #4 –
I have had that happen to our 03 U320.  There is a bleed valve for the air tanks for the slides. It is located on the left side by the main axle. Our coach had a label showing the location.  I opened that valve to clear any moisture in the line and the slides have worked perfectly since then. It only takes a few seconds to clear that line.
Charlie and Mernie Matthews
2003 U320
2020 Chevy Equinox
18918

Re: 03 U320 slides

Reply #5 –
Ok so more troubleshooting and I have learned a little. 

Opened the aux tank water drain and it was dry

Tried extending the wardrobe slide with engine off no movement.  I can hear the bladder deflating when I turn the key.  I looked at the bladder and for about 10 seconds there was a decent gap then the bladder started filling up. Key still turned to the right.  I didn't check to see if it was tight all the way around but at that point I figured the vacuum system had failed.  Was able to repeat this several times.  At no point did the aux compressor run.

The pump is running with the red light on on every attempt but if that seal is not completely vacuumed up the slide is hung up by the seal and the pump won't push through it.

Fire up the engine let it build to 125 psi.  Then let it run a bit longer. Back to the wardrobe slide, turned the key back on and could see it completely retract the seal. Hit the extend button and it worked perfectly.

Got to the living room slide all worked just fine. 

I'm trying to understand the sequence of events between the room control panel, the HWH control boards, the vacuum switch on the room Manifold, and the compressor. 

So if I had a faulty vacuum switch on a room Manifold how can it work with engine running ?

What tells the aux compressor to run when vacuum is needed and met ?

Any insight on this would be helpful.  I will try and dig it up from the HWH library. 
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: 03 U320 slides

Reply #6 –
Ruminating on this... (engineers like puzzles...)

Without the main coach engine running, the aux compressor should come on to deflate the bladder when the key is turned.  If it never comes on, check the inline fuse in the aux compressor wiring.  There are 2 power sources for that aux compressor, and I wonder if the 12V resettable breaker power is for leveling, but the inline fuse might be for the slide bladders only.

The reason all works well with the main engine running could be that its compressor might now be the source of air for the bladders and the venturi that deflates them.
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: 03 U320 slides

Reply #7 –
Not positive on your model of coach.

HWH air compressor only runs for 2 reasons. When the hwh tank pressure gets low 85? and runs to cutoff 105?
Runs when auto level or you manually raise up to level.

You need to figure out why your compressor will not run, either no power, bad solenoid, bad pressure sensor, or bad motor

If you are getting air to the HWH slide bladders without the compressor running and DOT tanks at 125 you have a bad check valve by compressor

2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: 03 U320 slides

Reply #8 –
Just so you are aware, when you turn the key to move the slide, and the yellow light starts flashing, the system dumps the pressure in the bladder and uses the venturi solenoid to pull a vacuum on the bladder.  This is why you see it collapse, then once the light goes solid, the bladder will relax as it no longer is under vacuum.  When you press the rocker switch to move the slide, the vacuum venturi activates again and pulls vacuum on the bladder again.  Once enough vacuum is present, indicating that the bladder is fully retracted away from the slide, then the slide will move. 
Keith
2003 U320 38' #6197

Re: 03 U320 slides

Reply #9 –
Thanks Keith,

So what is telling what that enough vacuum is present and to start moving the room ? Or is it assumed that everything is working properly without a positive indicator ?

 I believe my problem is right here.  Something was told or believes there is enough vacuum when in fact there is not thus the hydraulics are pushing the room out against the bladder and its not moving. 

I was also under the impression from past posts that the yellow will flash 41 seconds while waiting for deflation and vacuum.  Maybe that doesn't apply to the HWH 2000 on my 03 U320.  Others have posted their coach needed more time before pushing the button.

I see a vacuum sense circuit on a board but cannot find reference in literature yet. 

I'm gonna add vacuum gauges to the bladder air lines on the output side of the manifolds next.
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: 03 U320 slides

Reply #10 –
Quote from: Charlieboise –
So what is telling what that enough vacuum is present and to start moving the room ? Or is it assumed that everything is working properly without a positive indicator ?

Starting with 2003, there is a vacuum sensor.  Prior years only used time.

Quote from: turbojack –
You need to figure out why your compressor will not run, either no power, bad solenoid, bad pressure sensor, or bad motor

As turbojack points out, have you checked this and the inline fuse yet?  Without the aux compressor running when the coach engine itself is not running, you're not going to be able to pull adequate vacuum on the slide bladders.  Since you stated the slides will work with the main engine running and coach air tanks built up, the problem points more to the aux compressor than a vacuum sensor.
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: 03 U320 slides

Reply #11 –
Thanks Michelle,

Haven't been at the coach today and will look at it Monday with gauges in hand this time.  I will post findings then.
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: 03 U320 slides

Reply #12 –
I'm pretty sure the hydraulics have the power to push the slide in/out even if the bladder was inflated.  It would likely rip it or damage it, but the hydraulics are strong. 

The vacuum sensor Michelle mentions is there as when my bedroom bladder was intact, when turning the key, the light would go off within maybe 15 seconds.  My bedroom bladder is torn now, but the light does time out even with no vacuum after pushing the retract/extend button for maybe 20 seconds or so, then it will move the room.

Seems like step 1 is to verify that your pump isn't working...sounds like it isn't, and fix that.  Then see what other issues you have.  Gauges are a great addition for troubleshooting.

Here's what I did:  Aux Air Compressor running but will not deflate the bladder when extending!
Keith
2003 U320 38' #6197

Re: 03 U320 slides

Reply #13 –
Update:

Finally got the pressure/vacuum gauges installed on the room manifolds, aux tank line, and did some more testing.

Since I'm not finished with my diagnostics I won't get into all of the details just yet.

When operating the slide panel:

1) The aux compressor will kick in once the pressure in the tank drops to 70psi. It's set for 90/70

2) living room slide pulls 15Hg. Slide seal does not appear to be fully retracted (seal resting on slide top) but was able to extend room 3 times but 4th time failed. Hydro pump was pushing against the seal. Waited 1 minute no change in seal appearance. Aux compressor kicked in, no change in seal appearance, Pushed extend and it worked. Gauge read 15Hg during every test

3) wardrobe slide pulls 0Hg. Worked as Keith described.

It appears that when the tank is below 80psi the problem is more likely to occur. This may explain why when the cummins compressor is running it keeps the pressure up better.

I'm going to set the pressure switch to 100/80 and see if I get better consistency.

So some questions/comments:

1) if the LR seal vacuum stays steady at 15Hg why does the room seal not completely suck back into the frame ? I have a slow leak in the line but the gauge should be the tell

2)  the wardrobe seal staying at 0Hg and looks fully retracted is confusing me

3) should the aux compressor run irregardless of current PSI when slide room vacuum is required ?

4) when the 4th attempt failed on the LR slide why did the pump try to push through the seal ?

I will do some more testing and see if I can find the exact condition when it fails. 
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: 03 U320 slides

Reply #14 –
I really appreciate the help with one.  The members of this forum are amazing.

So here is what I have learned.

 If my tank pressure is below 80psi it's likely not enough to generate required vacuum. 

 If the pressure was below 80, the slide room control light was solid, and the seal was deflated but NOT fully retracted via vacuum the system understood it needed to pull vacuum. 

In order to pull vacuum when the pressure was  below 80 the compressor would kick in, the system assumed it had pulled enough vacuum but the compressor needed time to fill the tank and the hydraulics kicked in pushing against the seal.

Hope that made sense.

 Now that I have changed the kick-out/kick-in on the pressure switch to 100/80 I have not seen a failure.  This explains why when running the cummins I have enough pressure to through the slide sequence.

Thanks Keith for helping me understand the slide room sequence. 
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC

Re: 03 U320 slides

Reply #15 –
if its your hydraulic pump  ,it might have lost its ground. to test grab a nice looking screw driver that is insulated and touch the outer motor case to the ground terminal  if it runs when you make the ground  that your motor ground is toast. you will need 2 people for this one pressing the button and the other establishing the ground
2003 Foretravel u320 build 6066
cummins 450 ism
2008 Jeep Cherokee Toad
former Country Coach Owner.
Part time Rv er
Never afraid to learn.

Re: 03 U320 slides

Reply #16 –
Quick update:

The inconsistent behavior is explained by a faulty master relay.  Someone had used the intermittent relay in place of the continuous duty version.  The relay was shot after two years.

Part number for master: trombetta 684-1211-012 : Trombetta 684-1211-012 12VDC Contactor PowerSeal: Amazon.com: Industrial &...

Part number for pump side: trombetta 684-1211-212 : Amazon.com: Solenoid, Trombetta, 684-1211-212, 684-1211-212-06, In USA ready...

Thanks to all for input and guidance.  Now carrying a spare for both of the above.
2003 U320 40 AGDS Build 6157 161K miles

Hampstead NC