So my A/C is not blowing cold and I took it in for diagnosis. Turns out the low pressure hose is cracked. So I ordered a new one (should be in Friday) and was reviewing the procedure for recharging the system (I have a copy of the Infinity Service manual). It looks pretty cut and dry but I'm wondering if I will be able to do this effectively in my driveway. Its simple enough to replace the hose and then shoot some new refrigerant in there, but from what I can tell the refrigerant can be contaminated by the moister in outside air. Being that the system has already vented, outside air is in the system. Thus the whole evacuation procedure correct? Do I need to evacuate the outside air before recharging the system? The recharging kits from the auto parts stores don't have an evacuation tool. What should I do?

5/7/2009 1:34:41 PM

youre gonna want to get all the old shit out first. And taking the valve out or poking it with a screwdriver isnt the right way. It will need to be vaccumed out.

5/7/2009 1:58:10 PM

Where are you located? I can pull a vacuum on the system after everything's been put together, but I don't have the capability to evacuate a charged system.

You HAVE to evacuate a system that's been contaminated with outside air, and I recommend replacing the accumulator or receiver/dryer. Don't waste your money on one of those damned kits. You'll end up putting some leak sealer shit or other "additive" in there, or even more oil. And you don't need any of that as long as there's no sign of oil leakage.

5/7/2009 2:02:46 PM

^^ look retard, stfu if you don't know what the hell you are talking about, refrigerant doesn't go bad, and only the oil can get contaminated if the compressor fails

you need to add a small amout of oil, either ester or pao, whatever it calls for, maybe half an ounce or so to make up for what was in that line, the reason to pull a vacuum is to remove all the air from the system which changes the partial pressure of the refrigerant and decreases it effeceincy, if the system is only open for a short time to replace the hose, it won't get moisture in it

In short, yes you need to pull an absolute vacuum on the system if it has been opened, and it probably wouldn't be a bad idea to replace the receiver/dryer on a 7 year old car also, you need a good scale to measure the refrigerant going in, and a set of manifold gauges to verify the correct operating pressures.

zxappeal used to have most of that equipment, you may want to hit him up, i think his vacuum pump still works, mine burned up about a year ago



[Edited on May 7, 2009 at 2:06 PM. Reason : ^ beat me to it, dirty dan is back]

5/7/2009 2:05:45 PM

Yeah boy...LOLZ and thumbs up to the partial pressures comment, Keith...air is a noncondensible gas, and as such has an excessively high partial pressure when combined with R134. And the compressor can only maintain a certain pressure differential...not enough if air is in the system.

Get as much air out as possible. The vacuum also significantly lowers the boiling point of any moisture in the system and purges it as vapor.

5/7/2009 2:11:47 PM

you're making me think now, noncondensible gas is at atmoshperic pressure by cooling only right?

cause if you had a compressor that could reach the triple point of air...........$profit$

5/7/2009 2:14:51 PM

^^ ok yeah that's what I figured. I don't have the money to replace all those other parts right now. If I have to do it later then so be it. As it is the damn hose cost me $125 online and that's over $100 cheaper then what they wanted at the dealer.

I don't think you need to evacuate a charged system, the hose is cracked and all the refrigerant already vented to the atmosphere, or that's what I'm assuming since its not cooling.

So my plan is to replace the low pressure hose, have zxappeal vacuum the system and then recharge the system with new R-134a which has the lubricant in it already.

By the way I live in N. Raleigh near the intersection of Glenwood and Lynn. I wish I could pay you texa$ but i'm freakin broke right now. my wife has been with out a job for a few months (but she just got a new one just hasn't been paid yet...whoooot). I could definitely get you a case of your favorite brew though.

I'll be out of town Friday and Saturday but I'll be back in Raleigh Sunday afternoon and plan on replacing the low pressure hose then.

5/7/2009 2:15:33 PM

Not necessarily...think cascade compression with intercooling between stages. And lots of power.

5/7/2009 2:16:04 PM

i was talking in a mobile refrigeration system, not a damn liquid oxygen production facility

5/7/2009 2:17:03 PM

i never said anything about gas refrigerant going bad fuck face.

[Edited on May 7, 2009 at 2:28 PM. Reason : better words]

5/7/2009 2:26:34 PM

somebody on my facebook news feed thing just posted on somebodys wall about fixing their ac by having advance "recharge it with a can of charger"

5/7/2009 4:07:21 PM

funny

so how important is it to replace the receiver dryer (infinity calls it a liquid tank or dehydrator). does the desiccant become compromised if it sees air?

5/7/2009 4:17:09 PM

it'll be aight.

5/7/2009 4:19:03 PM

it'll work better if you replace it. piece of mind.

you don't have to use the cans with oil in them... actually don't.

put in what you need.

they sell cans of just r-134a. use that.

5/10/2009 2:05:42 AM

so i replaced the low pressure hose yesterday. but check this...when i disconnected the low pressure hose form the condenser side the system depressurized. i hear this hissing sounds and see green liquid coming from the connector. now call me crazy, but if the low pressure hose was leaking like the diagnosis that i got said, then shouldn't the system have already lost pressure?

5/11/2009 10:21:00 AM

Believe me, if the system had been under complete pressure, you'd have noticed. On a hot spring/summer day, that pressure will approach 90 to 100 psig. Even a system that doesn't operate due to excessively low refrigerant levels maintains some positive pressure.

5/11/2009 11:13:03 AM

ok cool

5/11/2009 11:45:12 AM

i'd replace the parts yourself and have a shop recharge it properly. That way they can check for other/additional/new leaks as well.

I just replaced the compressor, dryer, and all the hoses in my brother's jeep and thats what I need. Its not worth going through all the trouble just to have it leak again, or not work optimally.

5/11/2009 4:10:22 PM

right now i just want to get through the summer. if i have to replace parts next summer and have it recharged by a professional then so be it.

5/11/2009 6:04:20 PM

well if its not don right, you can look at changing belts, compressors, and a list of other expensive parts sooner than you want.

5/11/2009 7:54:42 PM

Quote :

"Believe me, if the system had been under complete pressure, you'd have noticed. "

and so would your neighbors. not that i have any experience with that.....

5/12/2009 8:07:40 AM

^^ so are you saying that by not changing the receiver dryer that all that other shit is going to break in 3 months?

5/12/2009 8:12:59 AM

he's saying by not charging it properly you can destroy a compressor fast. i'd at least have a professional vacuum/charge it for you with the right tools.

5/12/2009 9:16:39 AM

i agree...but zxappeal has the right tools and the experience to do it properly

5/12/2009 9:45:02 AM

Pulling a vacuum on the system for a good 2 hours can help if you elect to NOT replace the receiver/dryer...

The big thing is that PAG is hygroscopic...it attracts moisture. When it does, it can degrade into acidic components and promote system corrosion and premature failure.

Being that you still had some positive pressure, and the system wasn't open for long, I think you're probably okay.

5/12/2009 10:43:55 AM

Quote :

" he's saying by not charging it properly you can destroy a compressor fast. i'd at least have a professional vacuum/charge it for you with the right tools. "

yes

5/12/2009 2:46:26 PM

damn,an intelligent response

5/19/2009 9:34:01 PM