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Simple, Cheap Recovery?

jeffk14 on Mon May 14, 2007 3:14 PM User is offline

What is the absolute most simple, cheap way to recover refrigerant and be in EPA compliance without buying a lot of expensive equipment? I've read about recovering with gauges & tanks only. How is this done? Does the empty tank have to be evacuated first & if so, how many systems can one recover into a vacuumed down tank without a recovery machine? Thanks.

Dougflas on Mon May 14, 2007 6:47 PM User is offline

put an inline filter on the input of the recovery tank. Evacuate the tank. Place the tank in a freezer. Get the engine compartment hot. Connect the gauges to the system and recovery tank. Leave tank valves closed. Open gauge handwheels. Crack the connection at the tank to bleed the hoses. Open the tank handwheel. MOst all the freon will wnter the tank. Be advised, you have recovered the freon and not cleaned it.

mk378 on Mon May 14, 2007 7:07 PM User is offline

A new tank has to be evacuated or you will mix air with refrigerant. Once the tank has some refrigerant in it, it does not have to be evacuated before each use, as long as you're sure it is clean.

Merely having a vacuum in the tank will not be enough to pull all the refrigerant out of the system at room temperature. The pressure in the tank will quickly rise unless the tank is very large. But if you used a very large tank, it would not be possible to get the refrigerant to go back into the car when you're ready to reuse it.

The important point is to keep the tank very cold so all the refrigerant will (eventually) condense in it. If you have air in the system this method won't work so well, but on the other hand most of the air will remain in the car. Ideally the tank should be just large enough to hold the whole charge in liquid form, with some headspace for safety of course.

Test Specimen on Mon May 14, 2007 8:22 PM User is offline

FYI, the tank would have to be less than -21 degrees F to lower the pressure to less than 4 inches of vacuum (the EPA requirement) with R-134a. You would need to be less than -29 degrees for R-12. Packing dry ice around the tank is about the only way to get it that cold.

If you don't pull a good vacuum first to remove the air, it will be much more difficult to distill the refrigerant out of the system into the recovery tank. Also, the oil in the system will slow up the transfer process unless you can warm up the system prior to recovery so the refrigerant releases from the oil faster.

GM Tech on Tue May 15, 2007 8:50 AM User is offline

If you pack the recovery vessel in dry ice you can pull 24 In Hg on your gage set after all refrigerant has transferred- I use to do this before recovery machines were available-- I did this as part of my analysis to know how much (by weight) refrigerant was in a system..

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

jeffk14 on Tue May 22, 2007 9:32 AM User is offline


How about one of these? Will it work? I wonder if it meets the letter of the law for compliance.
http://www.icorinternational.com/literature/PDF/SPPS.pdf

webbch on Wed June 06, 2007 1:17 PM User is offlineView users profile

Quote
If you pack the recovery vessel in dry ice you can pull 24 In Hg on your gage set after all refrigerant has transferred- I use to do this before recovery machines were available-- I did this as part of my analysis to know how much (by weight) refrigerant was in a system

I'm completely new to this - still waiting for my recovery cylinder to arrive, but want to recover the refrigerant from my '92 accord to verify the correct charge amount. This dry ice method seems appropriate for what I want to do, but a filter between the gauge set and refrigerant tank would seem to be a wise addition as mentioned. If so, I was wondering what refrigerant filter to get - AMA sells replacement filters for their recovery machines - is that the appropriate one? Which hose do I need to get to connect to the service gauge set to the filter and refrigerant tank? Thanks



Edited: Wed June 06, 2007 at 1:18 PM by webbch

ice-n-tropics on Wed June 06, 2007 4:41 PM User is offline

GM TECH,
When it is absolutely necessary to know spot-on the exact weight of recovered refrigerant with the solid state CO2 method, I weigh the container 3 times during the procedure. This is so that the recovered oil weight can be subtracted from the delta weight of full cylinder minus original empty cylinder weight. A insulated storage cooler is helpful to extend the life of the frozen CO2. I don't use a filter in the line because more error may be introduced.
As our consulting Scientist noted, the absorbed refrigerant in the oil slows down the recovery (unless a heat gun is applied to the R/D or ACC and the evap blower is run on low).
Cordially,
ICE

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Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

GM Tech on Thu June 07, 2007 8:54 AM User is offline

I eventually went to an immersion cooler made by cryocool- neslab industries- this would produce a methanol bath of -125 deg f- worked great- did this for years until recovery machines were the standard. I never had any trouble with pulling out oil- as long as I took it out as a gas and not a liquid- was a slow process-but very accurate- usually took a half hr or 45 minutes- I always put a hair dryer to the a/d and ran the evap fan on low to help boil out the refrigerant.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

NickD on Tue October 27, 2009 10:28 AM User is offline

Is there really such a thing as a cheap vacuum pump or a cheap way to recover? Suppose you could go in for heart surgery to a doctor that uses an ax and a chain saw.

But lets talk about recovery and why the EPA is putting such an issue on only techs doing the recovery. First off the major cause of an AC failure is leaks that can be of two different kinds. A gas leak that simply renders the system as being worthless, typical leaks like this are using extremely poor grades of aluminum alloy in the manfucture of AC components, quick couples and the newest one, quick couplers for R-134a ports where a relatively large piece of neoprene is suppose to reseat it self perfectly when opened. Besides that, in particularly in the high side port exposed to extreme heat, that neoprene becomes brittle and hard.

The worse kind of leak typical in Ford quick couplers or GM single lip seats mounted way down below has the gas pressure pushing out the all important lubricating oil that leads to catastrophic compressor failure and plugged parallel flow condensers. Since gas pressure is still present, system keeps on working until you hear your belt break or squeal rather loudly.

Very seldom I even see a system that requires recovery, when I get to look at it, the refrigerant is long gone. When I opened the hood of a vehicle, I see pure unadulterated crap, dried up baked O'rings to make assembly easier, poor single lip seals when GM already had a good ceramic seal that lasted forever. Condensers and evaporator made out of the cheapest aluminum money can buy and those incredibly stupid R-134a ports where in some cases, have to replace an entire line where before, a 50 cent Scharder valve could even be replaced without discharging the system.

So why is the EPA on our backs and not on the backs of the people making this crap? Only thing I can think of, we live in a politically corrupt society so our leaders can get a few extra bucks for their campaigns. Government for and by the people, what a load of crap.

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