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Recovery/disposal alternatives

efxengr on Mon August 13, 2012 4:02 PM User is offline

Refrigerant Type: 134a

What are the alternatives when you want to drain the system down to make repairs or weigh in a new charge from scratch if you dont have the recovery equipment? No doubt the first is take it to a shop and have it evacuated but is there an alternative? Can you pull a vacuum on a 30lb cylinder and fill through the manifold then take the cylinder to a shop? I'm assuming that the vacuum pump has to have a free discharge and cant be connected to any receiver, etc.

Edited: Mon August 13, 2012 at 4:04 PM by efxengr

TRB on Mon August 13, 2012 7:16 PM User is offlineView users profile

Use the search feature on Dry Ice. That should entertain you for a while.


When considering your next auto A/C purchase, please consider the site that supports you:

efxengr on Mon August 13, 2012 9:43 PM User is offline


I think I found the answer I'm lookin for.

Go Dawgs!

Leggie on Mon August 13, 2012 11:06 PM User is offline

If you have one of those California approved self shut-off cans, you can hook up a hose that doesn't have or have the check valve disabled. It's basically setup like an aerosol can.

Use one that's almost empty, so there's no air inside. Hook it up to the system and pull the trigger open with zip tie. Soak it in a mixture of dry ice and denatured alcohol.
You'll have to use 2-3 cans. Don't over fill.

These cans are not meant to be refilled, and per DOT regulations, it is illegal to carry refilled cans in your car.

If you use a 30 lb recovery cylinder, you will have about a pound of refrigerant trapped in the tank that you won't get out without a recovery machine. The best way to prep a recovery cylinder is to pull a vacuum on it, then immediately fill it up with about a pound of new R134a. Once there's some liquid in it, you can dry ice it to recover from system.

Once you "prime" the cylinder with about a pound, you can reuse every pound that you recover... but... there's no way to tell how much oil got sucked out of the system in recovery process.

You could always build a recovery machine with an old fridge compressor. Fit two 1/4" fittings on an accumulator and use it sideways so oil doesn't go into the compressor.

Weight the accumulator first to nearest 1/10g. Weight it again after use. The weight gain after use/ oil density = amount of that you sucked out and needs to be replaced.

Edited: Mon August 13, 2012 at 11:09 PM by Leggie

mk378 on Mon August 13, 2012 11:37 PM User is offline

Be careful with the small cans. There's actually a sensible reason why it is illegal to refill them; they are very dangerous if improperly filled. Any container will burst if closed up when completely full of liquid refrigerant with no space for expansion. You need about 10% "head space" above the liquid to accomodate temperature changes. Don't start any type of recovery unless you're sure that your recovery vessel has sufficient space for the whole charge.

Edited: Tue August 14, 2012 at 9:28 AM by mk378

AutoCool on Tue August 14, 2012 3:24 AM User is offline

Looks like potentially deadly advice here. Dry ice, juryrigged aerosol cans, etc. Might as well use liquid oxygen and acetone, huh. Shame on you. I would recover the refrigerant free of charge just to keep this guys face being blown off from this sort of advice. People get hurt badly ALL THE TIME.

TRB on Tue August 14, 2012 9:29 AM User is offlineView users profile

Who told him to use "Dry Ice" Autocool? If you read though the different links you would have found, that the damagers of this type of reclaiming was discussed. Of course its wise it use the proper equipment. We tell people this everyday, yet they add propane, sealers magic oil among other things to their systems all the time.


When considering your next auto A/C purchase, please consider the site that supports you:

efxengr on Tue August 14, 2012 11:34 AM User is offline

I did. While I appreciate the creative ingenuity at condensing refrigerant I gotta go with Iceman's response in the following link

about having it evacuated. Thus the comment "go dawgs".

Not sure I would trust home-recovery since there's no way to neutralize the low pH, etc,......better off buying new.

I was basically looking for an alternative (on the weekend or at night) when wanting to clear a system out (legally), make a repair, and start with a clean/weighed charge to eliminate guess work. I have a few 20 lb cylinders that, if vacuumed down, depending on the system charge/volume, could at least take it to 0 psig or lower. They are rated 4,000 psi (and current) so no problem with pressure rise at ambient. The hope was to take them to a shop for proper withdrawal and disposal. Don't even know if a shop would do that but I'll ask.

Wait, propane? PROPANE? Who's adding propane?

Thanks for all the ideas and comments.

Edited: Tue August 14, 2012 at 11:37 AM by efxengr

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