AC resurrect - costly mistake
 

My truck has a dealer installed ARA aftermarket AC in it. Recently I decided to replace everything under the hood but keep the rest. Purchased all necessary parts including all the tools necessary to crimp, vacuum and charge the system. In the process I installed the new sanden compressor and ran the hoses through the firewall but did not attach them to the evaporator yet. I drove the truck to help someone move and it was very rainy. I was getting, what I thought at the time was water, leaking out the bottom of the drain on the evaporator casing.

A couple of days later I completed all the connections, belts, pulleys etc and decided to vacuum and charge the system. Knowing the compressor wouldn't charge with the hi-lo pressure switch hooked up I bypassed it and proceeded to charge it. Everything was going fine. It took about a pound and a half of freon and I paused in the charging to go check temps at the vents.

Then it all went downhill. My compressor stopped turning and my belts started screaming at me. I immediately shut everything down and went to look at my setup inside the cab. I noticed the watermarks from the drain were still there and it finally dawned on me that perhaps they weren't water marks. Sure enough, it was oil. Apparently my compressor oil had gravitated in through the hoses, into the evaporator and out the drain. I had just charged my system with no oil in it and apparently fried my compressor.

I played with it again on Saturday because I could take the belts off, engage the compressor through the switch and turn it by hand. However, as soon as it gets under about 25lbs of pressure in the system, it stops again.

Am I correct that my compressor is fried? Could I have damaged anything else that I need to replace prior to attempting this again?

I spent so much time reading, watching videos, purchasing the tools, etc that I really want to learn how to do this properly but now I am a little gun shy to attempt again. I really want to because I have a couple of other vehicles that I want to put AC in and don't want to pay someone else. Any good pointers for me at this point?

Re: AC resurrect - costly mistake
 

Please don't take this the wrong way but here is some good pointers..


" Sure enough, it was oil. Apparently my compressor oil had gravitated in through the hoses, into the evaporator and out the drain."

This statement indicates you do not understand air-conditioning principle and should not attempt this type work until you can get proper training.

Is there a vo tech or a local training center in your area that can provide you with some education and training in refrigeration? You need to know what you are doing so you will not make costly mistakes. This means you or others can get hurt.

AC is a closed system and compressor oil will not drain out unless something is not sealed.

Re: AC resurrect - costly mistake
 

He already said he didn't attach the evaporator, so the system wasn't closed.

Re: AC resurrect - costly mistake
 

I would say the compressor is shot. Did you by some way have the switch on while helping your friend move without knowing it was on? The compressor shouldn't have pumped the oil out inless the switch was left on. Something had to tell the compressor to come on.;):chevy:

Re: AC resurrect - costly mistake
 

If you do not have a charge in the system, the compressor will not engage. I doubt that you fried it in that short amount of time. You may have lost some oil out of the system, but it is not bone dry unless the compressor was engaged while you were driving around with the system opened up. I would hook everything back up, evacuate, and recharge again. If you are unsure of yourself, take it to a shop.

Re: AC resurrect - costly mistake
 

There is no way the compressor was "on" because I did not have a belt attached to it. I am baffled by that part of the whole deal. I know this sounds like I am an idiot, and in some ways I am, but I assumed it would be safe to drive since nothing was connected yet. I did not even have the switch connected at this point since the whole top portion of the inside unit was out of the truck. I simply had the evaporator and the two hoses coming in from outside that were loosely connected to keep them from getting contaminants in the system.

Re: AC resurrect - costly mistake
 

If nothing was hooked up then try putting some oil in the system and doing all the recharging over and see what happens. It can't hurt anymore than it already does.:chevy:

Re: AC resurrect - costly mistake
 

Unfortunately the one tool I did not buy is an evacuator. Unless someone knows how to evacuate a system without one, I am kindof stuck at this point. I know 134a is ozone friendly but the problem is the oil will remain in the system and I won't know how much is in there. Ideas?

Re: AC resurrect - costly mistake
 

Dude, you need to evacuate the system. That is the most important part of the process. Without doing an evacuation, you are spinning your wheels. Take it to a shop.

Re: AC resurrect - costly mistake
 

Re: AC resurrect - costly mistake
 

An evac pump is probably one of the most important tools. Get some training. Any clue what chemical reactions occur when you mix moisture (atmospheric) with refrigerant? If you are going to be doing this to other vehicles it would a huge advantage for you to get some proper training and know what you are doing instead of guessing.


I'm out........

Re: AC resurrect - costly mistake
 

Point of clarity. On the initial install, everything was new except the evaporator which I completely flushed and cleaned with ac cleaner. I did pull vacuum on the system prior to doing any charging. I did not evacuate it however because I assumed I didn't need to since it was new with NO freon in the system and only the oil that was in the compressor when it came.

Re: AC resurrect - costly mistake
 

How did you pull vacuum on the system without a vacuum pump? :confused:

Re: AC resurrect - costly mistake
 

My terminology is probably wrong. I have an ac vacuum pump and pulled vacuum on the system for 45 minutes prior to charging. I assumed an evacuation system was different than just a vacuum pump.

Re: AC resurrect - costly mistake
 

Ok , the only way the oil could get out I can think of is you have the hi-lo ports to low as in your sanden is clocked wrong , you got any pics?
I don,t think you are screwed yet you may have other causes.

Re: AC resurrect - costly mistake
 

I don't have photos but I know that is not the case. They are both vertical or close to it. The compressor sits almost exactly level with the two ports branching up from the top. The high side line is a 135 degree fitting that comes up and then loops down as it runs through the front to the condenser. The low side port comes up and turns 90 deg back to the firewall. Both lines have climbing to do in order to have oil get to the evap which is why I am confused. In order to have traveled the lines, it would have to have either back fed through the low side or travelled all the way through the condenser, drier and back through the firewall. I simply can't find a logical explanation for it.

The other thing is I know there are no leaks because after I charged it initially and it "froze" up, I left the system alone for a few days and when I hooked the guages back up, I still had the same readings on both high and low side. No pressure loss.

At the end of the day, I will probably have to take to someone that is "trained" but I would sure like to understand why it did what it did.

Re: AC resurrect - costly mistake
 

Did you have a set of refrigeration gauges on the system when you were running it ? If so what was the high side preasure? If you had any air in the system, it wouldn't condense and your high side preasure would be so high it could stall the compressor and cause the belt to slip. This could also happen if you put too much refrigerant in the system.

Gary

Re: AC resurrect - costly mistake
 

I did have a set of guages on when charging. I don't know how high the high side went because I was running to shut off the system. Currently it is measuring the same as the low side at about 25. Your explanation does sound possible. Maybe I didn't run vacuum long enough.

Re: AC resurrect - costly mistake
 

I believe that you are suffering from the basic, (Don't have enoguh freon to make it work right problem). On that note a couple things need to be brought forward, here. #1. A/C Compressor oil is a "DRY" oil---in other words it basically is dehydrated and has no moisture in it. If the compressor has been open to the atmosphere and it was a rainy day, then you have a compressor that has a lot of moisture in it, since the oil is nothing more than a sponge. #2 It is important to pull a good vacuum on a system and use charging gauges to see that the vacuum is holding to keep the system tight. It would be good to get the vacuum down to around 30" hg. That will remove the last of the moisture from your closed system. so this is the most important part. #3 You can charge more oil into the compressor, using a good charging manifold and gauges. #4 Once connected, be careful to not overcharge and kill your system that way. Are you charging with R-12 or R-134 freon? The R-12 is a lot more easier to deal with, than the R-134, due to the fact that the R-12 can be slightly overcharged and not affect the cooling of the system, where the R-134 is more critical to get the charge right. If you overcharge an R-134 system it will only cause the system to freeze the cooling coil over and not allow proper cooling.

Re: AC resurrect - costly mistake
 

Thanks for the helpful input. I am learning alot. It is an R-134a system so I know it needs to be exact. More than likely I had moisture in the system and did not run the vacuum on the system long enough.

Re: AC resurrect - costly mistake
 

Here's some info http://www.redhillsupply.com/how-to-vacuum-pump-ac.htm

Re: AC resurrect - costly mistake
 

You can't leave a vacuum pump on too long, especially if the system has been open to the atmosfere for any length of time durring humid or rainy conditions. You can leave the pump on it over night, and heat also helps evaperate the moisture from the system. You can place a drop light next to the compresor to keep it & the oil warm and this will help drive the moisture out.

Gary

Re: AC resurrect - costly mistake
 

Keep in mind the dryer will get contaminated fairly quck when left open to the atmosphere. especially in humid conditions.