chevydrvr

iTrader: (1)

When I bought my car, the ac lines form the compressor were cut and I have no dryer or lines. I plan on piecing it all back together to make it all work again.

So, I've been searching around here and read that I should get a new dryer of the system has been open for more than a few hours? Could I just get one from a car in the junk yard and use that?

Also, I have read a lot about people getting their system vacuumed 32" for 30 minutes. What does that mean?

Anything that can be told about the a/c system, I would appreciate learning!

Thanks!

camaronewbie

Vacuuming means that, once it's all put back together, you have air trapped in there. You can't get the refrigerant/oil mixture into the system because there is air already trapped in it - so you have to vacuum out the air, so there is room for the refrigerant/oil to enter. The system is designed to hold a certain psi of gases - if you have air in there, then you can't get that psi of refrigerant in there.

chevydrvr

iTrader: (1)

Is vacuuming the system something you can do yourself? Why do they say 32" for 30 minutes? Iobviously get the 30 minutes part, but why the length?

gsf-87IROC

You want to hold it close to 30" of vacuum for 30 minutes(or longer if you like) to remove the moisture from the system. Moisture turns to a vapor in a vacuum...and the vacuum sucks the moisture out.

chevydrvr

iTrader: (1)

I understand why you do it now,but what is the 30"?

lonestar7

iTrader: (1)

That refers to the vacuum pressure (or actually the lack of pressure) that the pump pulls on the "inches of mercury" scale. Good vacuum pumps will have a gauge on them that show how many inches they pull, the higher the number, the better the vacuum.

chevydrvr

iTrader: (1)

OH i understand now! Is there any type of website that can tell me almost everyhting there is to know about a/c systems? I've researched quite a bit, but I want to make sure I know what i'm doing before it put this back together.

Reid Fleming

iTrader: (2)

http://www.robinair.com/acsolutions/...m/acvacuum.php

A good writeup on the hows and whys of vacuum.

The 30" of mercury is actually impossible. But we write that as a way of saying 29.9" of mercury. Essentially, you're sucking the system down below 0 psi and then some. Holding the vacuum for half an hour to get rid of moisture.

What happens is that the boiling point of water changes (gets lower) the deeper the vacuum. At zero vacuum (ambient pressure...0 psi), the boiling point of water is 212°F. Under a deep vacuum, the boiling point of water can be 10°F.......Now assuming that you live some place where it's warmer than 10° in your work area, any moisture in the system will boil itself out. The vacuum pump will have a spot where little amounts of water vapour will puff out.

Getting as much moisture out as possible will prolong system life (less corrosion) as well as improve performance. Air is hard to compress in a vehicle A/C system. And moisture (water) is a terrible product to use as a compressible cooling medium.

Remember, water boils at 212° while R-12 boils at -21°. R-134a boils at -15°. Getting as much air and moisture out of the system is the way to go.

chevydrvr

iTrader: (1)

Wow, thanks that helped!

QChevyBoi89

I recently charged the A/C with oil and refrigerant. At first, before doing any thing, the compressor clutch did not engaged at all. After I charge it with refrigerant, the clutch would engage on and off but no cold air would come out.gauge reads full freon.

UnderCover89TBI

iTrader: (25)

really should vacuum for a minimum of 30 mins. I do an hour when I can. deffinately want a new drier. they come vacuum sealed new for a reason. change the orifice tube also. and a system flush wouldnt be a bad idea. they sell flushing solvents for a/c at your local parts store. use that and some compressed air to get it taken care of. good luck.

QChevyBoi89

alright thanks

UnderCover89TBI

iTrader: (25)

you welcome, hope it works out for you!