[bikestuff]

Gang,

I have been playing with the compressor in my coach. (long story, another thread)

I learned something about my coach that others may find interesting. If you have slides....do you know the source of the air for the seals? I always believed and would have bet money on....that the air for the seals comes from the rear air tank that is supplied by the 12V air pump. I thought the purpose of the 12V pump is to backup the 120V air compressor. That made sense to me. You really, really want to have air for the most important systems (the toilet, doors and seals).

The tank in front of the rear wheels can take pressure from the 12V as well as the 120V compressor and has a check valve so that it won't backfeed.

Here is what I learned today: The front slide seals are supplied from the tank near the 120V compressor. The rear slide seals are supplied from the rear tank. I am shocked.

The way that I figured this out was by turning off both air compressors. Then I let the air out of the front tank by releasing the petcock. I just happened to look at the front slide seals. (deflated). I then looked at the rear slide seals....(inflated).

I have often left the coach with the 120V air compressor turned off....believing that the 12V air compressor would keep the seals inflated. (I was wrong).

So the moral of the story...Even things that you are sure that you understand....well you may not be correct!

For what its worth!
Cheers,
bill
ps. If anyone has a better explanation please feel free to correct the record.
pps. If anyone does the same test, please report your findings.

[RussWhite]

Bill,

Interesting. Having nothing better to do I tried the test. I turned the aux compressor off, and drained all the air from the right front air tank. I walked around the front slide seal was inflated. I got back in the coach to air up, and noticed the dash gauge for system air was not at zero, but was at about 30spi. Don't know why it was not at zero, but 30 psi would be more than enough to keep the seal inflated. I'll have to think some more about this…. Russ

[lbrachfe]

It takes only 20lbs to maintain the slide seal. I have found that both my slide seals stay inflated with the front tank drained and the compressor off, so they must be on a separate air line from the 12v and maintain pressure if you loose shore power....?????? Maybe different coaches have the air lines done differently, which would be no surprise since Newell was and is constantly finding new ways to engineer stuff.

Maybe the check valves prevent the air loss from the seal lines ?

[bikestuff]

I agree with Larry's thought...but when my seals were down....They were really down. So I must not have check valves in mine. (only 7 coaches after Larry's).

[RussWhite]

Decided to settle this one, at least for my own coach.

Dumped all air - front tank, rear tank, and fitting in engine compartment. All gauges, except brakes, at zero.

Both air seals still inflated. Obviously check valves involved.

Turned ignition on and switched both slides on and seals dumped.

Turned switches back to normal and key to off. Both seals stayed deflated.

Engaged 12VDC pump only.
Both seals inflated.

I am completely satisfied with this configuration.

Russ

[Yachts]

I was told like you originally believed that the 12 v is all that is needed to maintain doors toilets and seals. But bill you are special and your coach maybe different.. Btw we will be down your way in the next 45 days or so

[bikestuff]

As usual, I am kinda "special". I am going to do some more testing.

But can we draw a consensus about how it "aughta" work?

1. The seals should stay inflated no matter what you do with the tanks (check valves).
2. If you have air in the 12V tank then the seals should re-inflate if deflated.
3. If you have an empty 12V tank and turn on the 120V compressor (leaving the 12V compressor off) then the tank should fill.
4. The 12V compressor will not fill the 120V tank, but the 120V compressor will fill the 12V tank.

I know everyones coach is different...but would this be a common way for the air systems to work?

[RussWhite]

That is the way it works on my coach.