Automotive Air Conditioning Information Forum

I need to replace an expansion valve and the binary pressure switch on an R12 system next spring. I would like to be able to reuse as much of the R12 refrigerant as possible. I have a clean empty R12 tank. I read on this forum where it was mentioned that one could draw a vacuum on the empty tank, place the tank in a ice bath and be able to draw refrigerant from a system. How well might this work? I could have the engine compartment hot to help move the refrigerant.

Plan B: I have access to an old Flouromizer 3000h recovery unit - was my late father's. I am guessing the unit is mid to late '90s vintage. I can not find a manual for this specific unit. I found a couple of manuals for newer units - one here: http://s3.supplyhouse.com/manuals/13039 ... D_FILE.pdf. Image of the actual unit: I am trying to decide if it is worth the space to pack it into our Fusion for the trip back to the Detroit area from Houston this weekend - space is at a premium.

This recovery machine was underwater during the Hurricane Harvey flooding back in '18. The high vacuum limit switch has failed. I jumpered the switch and using some very old hoses, I connected the recovery unit to a gage set and the recovery tank and drew a vacuum. The time to draw the vacuum to 14 in Hg was very long (guessing 1.5+ hrs). I was thinking the old hoses were porous but the vacuum held steady for 18 hrs at which time I released it. The unit has a compressor oil port - does one replace the oil similar to a vacuum pump? Might it draw a vacuum faster if the oil were replaced? With out a manual, all I could do is replace the existing oil with the same qty. Next question - The recovery machine has an oil separator port - might I be able to measure the oil pulled out of the system during recovery? If so, does one open the port after the recovery process is complete or while it is in process? The curved red line shows where the tubing exists the box.

Why does the recovery cylinder have 2 fill ports/valves (unable to attach a 4th image)?

14 in Hg is no where near sufficient to properly charge a system, you need to shoot for 500 microns. I think I would leave it behind.
BTW you can still get cans of virgin R12 on eBay

You could contact Bacharach to see whether they can help with a manual. But with the flooding and the other questions you have about the old recovery unit—and wondering whether it will work at all—would compel me to leave it behind. I wonder, too, whether there's any R-12 in the system to begin with.

That leaves you with a couple of options:
1. Replace the parts, ensure that everything is sealed tight, and then recharge it with virgin R-12, which is still available, as mentioned.
2. Convert the system to R-134a, which will cost more in terms of the work required, your time, and new parts. But at least you'll be using a still-readily-available refrigerant in case you need it in the future.

Thank you both for responding.

I still have about 15 lbs of R12. I not desperate to reuse the refrigerant in the car. I know there is still R12 in the system - still cools if I jumper the binary switch. I have asked around a bit and have not found anyone who still has the ability to recover/reclaim R12 - while I own a couple of older cars, I'm not into the old car network/social scene.

I still have one R-12 vehicle myself. I do have cans of R-12 stored, all bought for less than $2 a can in "those days".

I have used my vacuum pump and a small canister no longer needed by my workplace to recover R-12. Nowadays, I'd have to buy dry ice to do this (I'd use surplus from work back then), and use waste alcohol from the lab. Canister is something like this:



Here's what I'd do. I installed an AC fitting to my canister. I pulled vacuum on the canister to remove any remaining refrigerant or air, then close its valve. I'd put the canister in the freezer. Then I'd put the canister in a dry ice-alcohol bath, attach the canister to the vehicle AC, open the canister's valve, and its vacuum would start to pull over refrigerant. As refrigerant arrived into the cold canister, it condensed into liquid refrigerant, so still was under vacuum, so more refrigerant came over, etc. When complete, I'd shut the canister valve; when filling, I'd just fill from the canister. I'd weigh the canister before and after so I'd know how much refrigerant was recovered.

Cusser:
Thanks for responding. I was thinking I should be able to recover most of the refrigerant with the method you described. I actually found the manual (dated '97) to my father's old recovery machine the day before we left the Houston area and it answered all my questions posted in the original message and I found in the manual that the high vacuum switch (sometimes) needs 1 to 2 PSI to reset so it might not have failed after all. So I squeezed the recovery unit and recovery cylinder into the truck of the car before heading north. So now I should have 2 recovery options next spring.