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| Re: [GMCnet] The Markbag(tm) [message #155812 is a reply to message #155811] |
Sat, 07 January 2012 05:28   |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| emerystora wrote on Sat, 07 January 2012 03:56 |
I belive what Hal is telling you is that if the compressor has a
higher cut out rate then, when the wheelwell valve stops floe to the
bag, the compressor tank will the fill to a higher pressure. If you
tjhen set the switch to Raise you will iniatilly get some air flow
from the tank to the bag before the compressor starts. If the
compressor tank begins at the same pressure as the bag you would not
get this "extra" flow.
However the volume of the tank is somewhat small so the amount of air
provided by that higher pressure (which gives the "faster response"
that Hal refers to) will be small but it does exist if the cut out
pressure is higher.
This is probably just acedemic as with the factory set up, at least
with the Electrolevel, the cut in pressure is lower than the bag
pressure so in order to raise one must first dump air from the bag
before the compressor will start.
I have long thought of wiring in an "override" so that I could start
the compressor with higher than cut in pressure already in the bags.
Has anyone done this?
Emery
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I'm not quite sure what you are trying to accomplish but I have my pressure switch set at about 112 cut in and 128 cut out. Would that take care of your problem?
I also installed an old firemen's air tank (rated at around 2000 PSI) underneath the coach. I have it as additional reserve air. It is probably 8 or 10 times the capacity of the puny tank that GM installed. I have a 12 volt air valve that turns the reserve tank on when the main tank air pressure switch calls for more air. I had to stick a capacitor across the coil of the valve to extend the delay time when the valve is shut off. This keeps the low air pressure switch from hunting or chattering.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] The Markbag(tm) [message #155845 is a reply to message #155815] |
Sat, 07 January 2012 17:43 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| emerystora wrote on Sat, 07 January 2012 08:12 |
>
> I'm not quite sure what you are trying to accomplish but I have my
> pressure switch set at about 112 cut in and 128 cut out. Would that
> take care of your problem?
>
>
Thanks, Ken
That is so simple a solution that it just somehow didn't occur to me.
Many times when I've wanted to level the motorhome I've had to dump
air to lower the pressure to get the compressor to turn on. I think my
cut in is at about 80 psi.
I'll have to check my pressure valve to see how to set the cut in.
Emery Stora
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OK, now I understand.
There are two adjustments on that switch. One adjusts the operating range or operating difference between on and off. The other adjusts the shutoff pressure. Try the range one first.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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