I recently installed the a/c system from a parts car I had to my daily
driver that did not have a/c (from a 1994 Honda Civic LX to a 1993
Civic VX) it was a direct bolt in. All the o-rings and such are in
excellent condition. However, due to my lack of experience, I am now
unsure how to charge it up. It requires 19.4oz. Any help is
You are better off taking it to a garage and letting them do it
right....that is if you can find a garage with a competant
technician...*cough* who will do you right....You want someone
professional....not some slackjaw grease monkey with a set of charging
Tim.... seriously....it will last longer if you take it to a
professional.....the extra money up front will actually save you money
in the long run.
This really isnt an auto forum, but since you asked, two things you
really must do....Change your reciever dryer. They are about thirty
dollars. They absorb all the moisture that entered the system when the
lines were open. Do not use a used one. That is like borrowing someones
stained underwear. Always replace!!!!
Next, makesure the systems is vacuumed and holds -27 psi for at least
thirty minutes. Water boils at around 70 degrees at -27psi. This will
help remove any moisture that is in the system. After the thirty
minutes, close off the vacuum and wait 5 minutes. if it doesn't hold
the neg 27 psi for 5 minutes, then you have a leak somewhere.
I new as soon as I hit send, I knew someone would bring up Colorado or
hi-altitude. All I can say on my behalf, is there is nowhere else in
the world like home. And in my home, ie my world, 27 is good!!!! That
being said, I humbly submit that the information I posted may work in
no-one elses world but my own :-)
I am also mistaken on the -27 PSI; in that it is not referred to as neg
psi, but inchs HG. Thanks for keeping me on my toes.
FUCK SCHOOL! Just hack it. That's good enough.
500 microns is satisfactory (in most cases); 200 microns is better,
and I like to see 50 microns or less. If 50 microns can hold for 20
minutes, under stable ambient temperature, you're good to go.
Any water will start to sublime, and pressure will increase.
Another way to check for leaks is put 50 PSIG of N2 in the system, and
walk away from it for 12 hours. Compensate for Boyle's law if the
goddamn temperature drops overnight. But I use a heated garage or
shop. The heat doesn't fluctuate more than 50 dehrees. I swear. Stick
it under Paul's collar to heat it is you're in such a big fucking
fucking hurry. No one wants to run at a Turtle's pace, anyway,
You know, I've worked for some real kooks (wish they were cooks
instead, because I always wanted to ce a chef) in my time, and my
PET PEEVE is doing a compressor change in a cold shop in winter. I
mean, fucking 40 deg F (or lower) temps INDOORS overnight, on
domestic fridges. I could charge to factory weight (using charging
glass) wit R12, BUT WE DIDN"T FUCKING USE R12!. Can't check suction
at 40 deg F ambient. Headpressure WAAAAAAAAAAY out of specs for cap
tube system. And before you go off half-cocked (pun REALLY intended),
I'm not talking about split systems, RTU's whether comm or resi....
NO! NONE OF THAT BULLSHIT! I'm talking about self-contained refers,
both home and commercial. In someone else's shop. I'm a fucking hack.
You wouldn't believe some of the shit I had to do.
That's why I work for MYSELF now.
No, the customer IS NOT ALWAYS RIGHT. SORRY!
Walking away is my specialty, and "Fuck you, dude, you're crazy!"
is my favorite line of rhetoric.
How does this tie in with HVAC? It's cooling - it's refrigeration.
OK? And FUCK YOU if you don't like it.
Oh, GOD... you have no idea what I have gone through (yes you do, if
you have been in the field, and especially in apprenticeship, and
had to work on home appliances for 20 years, working for stupid jerks
who "have no money" to do it right).
I am in a VERY BAD MOOD today. I had a BAD DAY yesterday.
And it wasn't even trade (occupation) related.
If you want to flame me, or are a troll, then FUCK YOU, and =plonk!
I wouldn't ming a bad hair day, for even bad hair pie would alleviate
my desparation. A word of advice: Don't piss off your old lady.
Sorry for the anecdote. I was just venting (no pun intended).
I know I need to chill (pun intended).
Today, I go through totally unrelated issues.
I am getting set up with voc/rehab, and getting into arts, and maybe
even computers, although I already know a little bit about computers
(do I really?).
School is good. You should try it sometime, you fucking hacks!
And Bill Surber has my permission to flame me, along with Paul
I DON'T GIVE A FUCK!!!
I'm having a good day, actually, too.
So, if I want to make a fool of myself in the newsgroups,
It's none of your fucking business. Just ignore/filter me.
I DON'T GIVE A DAMN!
If I have helped you, then help me keep coming to you, by writing
your name on the back of a $20 bill or on a money order, and postal
mailing it to me.
Have a nice day.
[original post is likely clipped to save bandwidth]
duh, the gauge can be calibrated in furlongs and work just as well ;)
First, vacuum should be absolute, not gauge so altitude means squat.
It just happens that most decent vacuum gauges are calibrated in
microns. _Usually_ PSI means someone is using a service gauge set, not a
well calibrated vacuum gauge.
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
I haven't heard of microns, other than I can figure they are probably
small. I know automotive systems pretty well, but probably not on par
with your knowledge. I stand by my statement of vacuuming for thirty
minutes to remove moisture in an automotive system. And that the system
should hold that vacuum for at least five minutes. If there is any
leaks in the system, you will see the vacuum drop before the five
minutes. As for the neg27 psi, as was pointed out, I acknowledge I
should have wrote 27 inches hg.
If you care to post anything else on microns, I would be interested in
learning about them and how they relate to the HVAC industry. After
this post I will try to do a google search on them. Have a great day
and thanks for taking the time to post. I really enjoy learning from
Whatever works for you I guess,.......go with it. Just wanted to make
sure you werent getting hung up on any of those "old rules" or that
"rule of thumb" bull.
We have a few too, like triple evacuation with nitrogen purging!!??? I
personally see no need for this with todays high efficiency two stage
That being said, I just ran across another stupid tid bit put out by
Carlyse. I changed out a 5 ton scroll compressor in a 7 year old
Bryant condenser. Right there in plain black and white from Carlyse
instruction sheet it said to just make sure you pull a vacuum to 1000
microns!??? Some things just never cease to amaze me. :-)
One HVAC guy I talked to tells me he was talking to an EPA guy.
Mentioned that he had a vac pump that would draw to 50 microns. He
said the EPA guy said that was not good enough. That in a couple
years, by law, all vacuum pumps would draw to 1,000 microns.
Dunno how true it is, but good for a smile.
Christopher A. Young
You can\'t shout down a troll.
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
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
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
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
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