Yah I can "see" it, but have trouble truly wrapping my head around it.
Thanks for attempting to get me to understand it. Bottom line: I have
a manometer.

I currently have my fridge hooked up to the LP system of van. Which
was known working. We'll see if it cools.

FWIW, the fact that I had the fridge in direct *late afternoon*
sunlight yesterday, may have affected how the the ammonia etc. and/or
other components of the fridge, worked. Even though I had it working
minutes before in AC.

I got cocky and thought I"d try it with a higher ambient temp. This
may have been the bigger factor in why it wouldn't cool on LP.

Neil.

On 7/31/07, Mike Rocket J Squirrel Elliott <camping.elliott@gmail.com> wrote:
> Nothing at all strange about it. This type of manometer measures the
> difference between the pressures on the two sides. If both sides are
> open, they are both receiving the same pressure on their tops
> (atmospheric pressure). Push down harder on one side and the other side
> goes up. Whether the hose is two feet long or 20 feet long, or whether
> it has 100ml or water or 1000ml of water the same volume of water is
> being lifted.
> ------
> * That's why these are "water" column inches.
>
> Mike "Rocket J Squirrel" Elliott
> 71 Type 2: the Wonderbus
> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> KG6RCR
>
> On 7/31/2007 1:54 PM neil N wrote:
>
> > thanks guys.
> >
> > Strange it seems it may not matter how much water is in tube.
> >
> > True?
> >
> > I imagine a LONG column of water would change the readings. Dunno.....
> >
> > Anyway.....
> >
> > FWIW, (for newbies like me) I made the manometer with 1/2" clear hose.
> > This fit over 1/2" copper pipe, but I heated the clear tube a *little*
> > with a flame first. Tight fit, but it works. 5/8 ID hose would fit
> > better. Use hose clamps.
> >
> > Make sure you use flared fittings. These are standard and I found the
> > brass fitting in the  Canadian Tire plumbing section.
> >
> > "  3/8" x 1/2" union" : plumbing
> >
> > Copper fitting in pic accepts standard 1/2" copper. (i.e. for fitting
> > 1/2" copper pipe to male threads of water tank)
> >
> > I used a little nylon tape over threads of brass piece. One could
> > solder the copper and brass pieces together if desired.
> >
> > Cheers,
> >
> > Neil.
> >
> >
>

--
Neil Nicholson. 1981 Air Cooled Westfalia.

http://web.mac.com/tubaneil