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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: sedelange on July 15, 2017, 03:50:25 pm

Title: Slide ready light
Post by: sedelange on July 15, 2017, 03:50:25 pm
Went to open rear slide and turned key switch on.  Light flashes and bladder deflates.  After 22 seconds light goes out instead of steady on.  Tried fron slide and same thing.  Any ideas.?
Title: Re: Slide ready light
Post by: sedelange on July 15, 2017, 04:01:36 pm
Started engine and retested slides.  Now with engine running they never stop flashing.
Title: Re: Slide ready light
Post by: Michelle on July 15, 2017, 04:20:38 pm
Do you see the bladders deflating when you turn the key?

Since the engine running only partially changes things, it's likely not the aux compressor (but do you hear it come on at some point after you turn the slide key but don't have the coach engine running?)

There was a recent (within the last year) post about this, but it was only for one slide, not two.  I'm pretty sure it was a slide bladder leak but let me search before I commit to that....  It would be VERY unusual for both bladders to go at the same time.
Title: Re: Slide ready light
Post by: sedelange on July 15, 2017, 05:09:32 pm
Either bladder will retract.  I am assuming vacuum switch.  I was in that compartment yesterday replacing level sensor.  Didn't think l was close to anything.  I now have to wait until garage drains.  I had coach pulled out far enough to run generator and then the thunderstorms hit.
Title: Re: Slide ready light
Post by: sedelange on July 15, 2017, 05:10:10 pm
I have never looked.  Where is the slide manifold located?
Title: Re: Slide ready light
Post by: sedelange on July 15, 2017, 09:19:52 pm
Thunderstorms quit so I went into equipment bay and found air compressor breaker blown.  Reset breaker, now pump won't shut off.
Title: Re: Slide ready light
Post by: sedelange on July 15, 2017, 09:22:02 pm
Finally quit. Seems like it ran 10 minutes. Everything working. 
Title: Re: Slide ready light
Post by: Mark Duckworth on July 16, 2017, 06:38:05 am
Started engine and retested slides.  Now with engine running they never stop flashing.
Steve,

After you started the engine, did you allow the front and rear tank pressures to build to full pressure before retesting the slides?  The front and rear tanks will contribute air to the slide out bladder air tank but only after the pressure in the front and rear is >= ~65 PSI.  At ~ 65 PSI the protection valves on the front and rear tanks open and feed air to the aux air system.  This pressurizes the slide out air tank.  This process might take a few minutes after engine start depending on the amount of air in the front and rear tanks prior to engine start.

Mark
Title: Re: Slide ready light
Post by: Jim Frerichs on July 16, 2017, 01:25:06 pm
Steve,

James Triana once told me the light on my slide panel is timed only at about 30 seconds and is not operated by air pressure for my coach. I am not at all sure if other years have a pressure controlled amber light??
Jim

2002 U320
Title: Re: Slide ready light
Post by: Mark Duckworth on July 16, 2017, 07:50:06 pm
Steve,

James Triana once told me the light on my slide panel is timed only at about 30 seconds and is not operated by air pressure for my coach. I am not at all sure if other years have a pressure controlled amber light??
Jim

2002 U320
On my 2003 the the yellow light changes from blinking to steady when the vacuum switch senses adequate vacuum has been achieved in the bladder.  The vacuum is achieved through the venturi effect that is produced by pressurized air. 

Venturi Effect (https://en.wikipedia.org/wiki/Venturi_effect)

The vacuum switch is shown in the attached drawing.

Edit: For James' statement to be true, it seems there would have to be source of vacuum other than pressurized air, e.g. a vacuum pump.  Perhaps I'm missing something but it seems that one way or another the air has to be sucked out of the bladder.

To clarify the drawing, please ignore the item labeled in red lettering as "vacuum switch".  The switch that senses vacuum is shown in the photo at the bottom of the manifold and in the drawing on the left of the manifold and is labelled "vacuum switch normally open".
Title: Re: Slide ready light
Post by: Michelle on July 16, 2017, 09:03:54 pm
James Triana once told me the light on my slide panel is timed only at about 30 seconds and is not operated by air pressure for my coach. I am not at all sure if other years have a pressure controlled amber light??
Jim

2002 U320

IIRC that is true for 2002 and earlier.  In 2003 (I believe) and later the system looks for vacuum level.
Title: Re: Slide ready light
Post by: Mark Duckworth on July 16, 2017, 09:08:28 pm
IIRC that is true for 2002 and earlier.  In 2003 (I believe) and later the system looks for vacuum level.
How do they exhaust the air from the bladder?  Do they create a vacuum in some way or just open the bladder to the atmosphere and allow it to self-deflate?
Title: Re: Slide ready light
Post by: Rich Bowman on July 16, 2017, 09:11:47 pm
It is just like yours except we don't have a sensor for the light, just a timer.

Rich
Title: Re: Slide ready light
Post by: Michelle on July 16, 2017, 09:16:24 pm
How do they exhaust the air from the bladder?  Do they create a vacuum in some way or just open the bladder to the atmosphere and allow it to self-deflate?

Not sure, but I would think venturi as you mentioned is a strong possibility since I recall ours always needing to run the aux compressor while deflating the slide bladders.

The difference between the 2002 and older coaches and the 2003 (I think) and newer is that the older ones simply worked off a timer; the newer ones actually look for a vacuum level to be achieved in the bladder before allowing the slide to be moved.