A/C question

Page 1 of 4  
A mechanic says he thinks I have a leak in my evaporator. When I attach a gague to the low pressure valve, it reads over 100 psi (way overfull) Is
this guy a dope, or is there something I am missing.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

the compressor should be running when you check the pressures.
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks.
I will try tomorrow. Shouldn't it read 0 if I have a leak?
Also, I am pretty adept at working on cars, but I am a supreme novice when it comes to A/C. Can somebody suggest a good book that I can read to get mor edjucated?
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

take your vehicle to a qualified service technician. a/c isnt something for the novice. you can bullshit your way through it with the $9 pressure gauge from pep boys, but you need to fix the leak before you bother with charging the system (unless youre just looking for a temporary fix).
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The thing is, I would really like to learn, and what a golden opportunity now that I have a broken system (I actually have two) to get some experience.
I am not afraid to spend some money on equipment, I just don't know what to buy, or how to use it.
If what you are saying is that it is too complicated, or involved for the do-it-yourselfer I respect that I guess.
Does anybody know a way that a guy like me could learn more?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The problem with AC is that you are dealing with high pressures and if you screw up, things can go wrong that can hurt you as well as damage expensive components like the compressor. Another problem is that many of the tools used for AC service and repair are pretty much useless for much else and are rather expensive. I myself look at the cost and usability of the tools and my time compared to the cost of having the repair done. If I have other uses for the tools or I know that I will need to use them again then I buy them and make the repair myself otherwise it makes more economic sense to just have the repair done for me. There are books on this stuff and if you really want to learn, I would go there first.
--
If at first you don't succeed, you're not cut out for skydiving
"Surfersabo" < snipped-for-privacy@cox.net> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
So what tools are so expensive that are required to work on an A/C system? I have been working on them for years and can't think of any tool that is that expensive. With a set of gauges and a book telling you what pressure at what temp you should be looking for I can't think of anything on an auto that is much easier to do than charge an A/C system.
Yes maybe a vacuum pump but if you are a little resourceful a used compressor out of an old refrigerator with a connector on it makes a great vacuum pump and basically free.
TBone wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
vacuum pump ($300). recovery unit ($800). recovery tank ($100), proper gauges ($100-$300). all sorts of hand tools.

i find this statement ignorant, foolish, and very irresponsible. you can _not_ pull adequate vacuum with a used compressor.
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

makes
no, but it IS handy for pumping the system down to see if it holds vacuum
if it holds, THEN hook up the 'big dog' overnight
and, BTW........if you find an OLD one (pre about 1980), you'd be surprised how good a vacuum it WILL produce
the new ones are for crap for this use, tho
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

so why go through the trouble to begin with? if you have the "big dog" (and youll HAVE to at some point before charging the system), why bother with a makeshift system just to see if it will hold the vacuum? besides, with proper equipment (a 2 stage vacuum pump) its pointless to bother with an overnight pull. a quality vacuum pump will pull it down just as hard in 15 minutes as it will in 24 hours.

it may produce more vacuum than the newer compressors, but it will _never_ produce anywhere near the 500 micron target which is required to pull out all the moisture and non-condensables. there are a _lot_ of home remedies that might get you by, but this is what makes the difference in 45 degree vent temps and 55 degree vent temps. having the proper tools makes the difference in a 3 year expected service life, and a 15 year service life.
if its 101 degrees out and you dont have any money i guess you do what you gotta do to get by. hell, i ran propane in my camaro a/c system when i was 17 lol. but in hvac/r there is no short-cut, and no way to save any money if you want to consider it fixed right.
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

vacuum
(and
because in central IL in August, you may have 2 or even three jobs going at once..............
I can 'test' one while I pump the other and charge a third

15
was
I never said there was, and I fix it right

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nathan W. Collier wrote:

So how HARD is HARD (atmospheres) ?

I think you have better find one and try it before you say that pulling that little bit of extra vacuum will product a colder vent temp. So how many atmospheres does one of these super vacuum pumps pull ?

I have found that when a HVAC system has really failed it should just simply be replaced with a completely new system. It ends up being the overall cheapest way to do. Usually the new system is so far more efficient that it will pay for itself in a couple of years.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
as previously stated, you need to pull a vacuum to at least 500 microns in order to properly evacuate the system of moisture and non-condensables.

done it _many_ times with any type of compressor you can name. having used a micron gauge on it i can tell you with authority that youll never achieve 25% of your target 500 microns.

it depends upon what you mean by "really failed". a minor leak is nothing. most of the charging products contain leak stopper and ive found it very effective in the past (if its a seal issue).
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
With any AC car, home or commercial when it's opened to the atmosphere you need to evacuate the system. Meaning you need to remove ALL of the air and moisture from the system. I have no clue what the cost of the equipment for evacuating and measuring a charge is for a vehicle but you're going to spend a grand or more for the equipment for similar residential equipment. That's assuming you have nothing to recover.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A $1,000 you got to be kidding. Be resourceful and it will not even cost $100. Yes if you are going ot follow the law then buy the recovery system but I find that most A/C is discharged anyway when it needs work and if you have to discharge a little of what is left then just close your eyes and do it. Also remember every auto A/C system is set up to leak and will. If you have to add a can every other year or even every year that does not mean you have to get it fixed or may not even be able to fix any better that that. Any place that you have a shaft with a seal around it will leak. Now that brings up a question, Why didn't the auto industry go with a sealed compressor and operate it off a a generator that generator a higher voltage than 12 volts to keep the current down. Now that would have been more of a environment fix that saying no more R-12.
Steve Scott wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Been doing this for years. My recovery system is a tub of ice and a Freon cylinder. Yes, it's slow. Yes, it does not remove every bit of Freon. But it does get all the liquid so you're not releasing much. As far as a vacuum pump. I use an old refrigerator compressor. They way you get the moisture out is you pull a vacuum. Wait to see if it leaks. Might have to do this a few times as Freon hides in the oil and takes a while to come out. Then you add a bit of Nitrogen, about 3 PSI. Wait a while and pull vacuum again. The Nitrogen will get the moisture out. While you're pulling vacuum the last time heat the receiver/dryer with a hair dryer. Before you ask, we have race cars that we use Nitrogen to control the throttle so we always have it. But, it's not hard to get and if the system has not been exposed to air a long time you can skip using it.
Al
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

you will NEVER under the best of circumstances achieve anywhere near (not even close) to the 500 micron target with a refrigerator compressor. you might think it works great for you and thats fine and well but dont mislead others into thinking your way works because it doesnt. it might enable you to get cool air from your vents but its not as cool as it would be if it were done right.....and your components wont last as long as they should. you arent pulling a deep enough vacuum to evacuate all moisture and non-condensables. sure it might get you by and im not busting your chops on this. i just dont want others to think this is an accepable alternative.
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hey Nate, where do you get your vacuum pump oil?
--
If at first you don't succeed, you're not cut out for skydiving
"Nathan W. Collier" < snipped-for-privacy@aol.com> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

i buy it in bulk at johnstones here in billings. i buy in bulk because i change the oil in my vacuum pump after _every_ usage as recommended by my vacuum pump manufacturer. this is why i attach a $5 vacuum pump charge each time i use it (although most companies charge 15).
why?
--
Nathan W. Collier
http://InlineDiesel.com
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Because the fluid in my pump is getting old and is about due for a change. Do you know of any retail places here in NC in the Raleigh area.
--
If at first you don't succeed, you're not cut out for skydiving
"Nathan W. Collier" < snipped-for-privacy@aol.com> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.