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Posted by ~^Johnny^~ on July 25, 2006, 11:34 pm
>I haven't heard of microns, other than I can figure they are probably
>small.
I prefer nanometers.
Of course, that's on Earth.
On Ork, they use nano-nano-meters,
and apply bubble solution with a dauber after spraying with Pam.
Then we replace the Mork fittings if they leak.
--
-john
wide-open at throttle dot info
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Posted by Bob_Loblaw on July 25, 2006, 11:47 pm
> after spraying with Pam.
If I had Pam, I"d spread her every chance I got!
--
Respectfully, Bob
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Posted by komobu on July 12, 2006, 5:14 am
Bubba wrote:
> Have you heard of microns?
> Bubba
Conducted a search and this is what I found on microns. Thanks for
educating me on them. I can see where the micron guage would be useful
if it can tell you how much moisture is in a system. I have never seen
these used in the automotive arena, but perhaps they should be.
Don't Forget Your Micron Gauge.
Pulling a good vacuum before charging a new system with refrigerant or
after a repair is essential for the proper operation of an air
conditioning system. Proper operation, its longevity, and the time you
spend at the jobsite all relate to dollars in your pocket. In addition
to the vacuum pump, a micron gauge is an essential tool. Below is a
description of how the gauge works and why it is used in the HVAC
industry.
Preventing Problems
A typical micron gauge.
A micron gauge measures the amount of air or "noncondensables" and
moisture in a system. The unit of measurement used is a "micron."
The gauge is placed between the vacuum pump and the middle port of your
manifold set. The lower the micron reading, the deeper the vacuum. The
deeper the vacuum, the lower the amount of air and moisture in any
given system. Why is this tool necessary? It can help you prevent
problems like the following.
Potential Problem #1
If moisture is left in the system, some of it will turn to ice when
refrigerant is introduced into the system. If enough moisture is left,
larger ice particles will form and can block the cap tube or piston,
causing a restriction in the metering device.
Potential Problem #2
If moisture and air are left in the system, they can form acids when
combined with chlorine (which comes from CFC or HCFC refrigerants such
as R-12 and R-22) and oils (from the compressor). Over time, these
acids eat away at the compressor's motor windings and cause premature
compressor failure.
Potential Problem #3
If moisture and air are left in the system, they can cause higher than
normal head pressures. These pressures can mislead a technician and
cause higher discharge valve temperatures, which again can cause
premature compressor failure.
Potential Problem #4
If a micron gauge is not used, a small leak will never be detected
using conventional gauges. Conventional gauges use inches of mercury
(Hg) to measure vacuum. Most gauges go down to 30 inches of Hg. If one
inch of Hg (at 32 degrees F) is approximately equal to 25,400 microns
of Hg (at 32 degrees F), you can see how much more accurate using the
micron gauge tool can be. It is recommended pulling new systems down to
400 microns or even less if time allows. If a leak is left in the
system, first you will experience indoor coil freeze-up, then no
cooling and/or compressor damage.
Money in Your Pocket
Taking the time to use a micron gauge to check for these potential
problems is not only a preventive measure, it can also benefit your
reputation as a contractor. Most micron gauges can be purchased for
$100-$400 depending on the model - a small investment up front that
can save you a lot of money in the long run.
Two More Things
But you're not done yet. Two other practices are recommended in
conjunction with using a micron gauge.
The first is purging the system one to three times with nitrogen before
the pump-down. The nitrogen absorbs moisture and can be released into
the atmosphere without any harm. This reduces the start-up time even
more.
The second is changing the oil in your vacuum pump regularly. Vacuum
pump manufacturers suggest changing it after every use. If the vacuum
pump oil becomes cloudy or saturated with moisture, it will reduce pump
efficiency and thus increase the time you are at the jobsite.
As you have read, pulling a good vacuum before charging is essential
for many reasons. Yet these reasons boil down to money in your pocket.
Those who use micron gauges and practice good pump-down techniques know
this. Unfortunately, those who don't will eventually learn the hard
way.
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