Refrigerant Recovery.
 

I have been thinking about Refrigerant Recovery Machine. I would not need to do this very often so low cost methods would be good.

I could watch craigslist or ebay for a good deal on a Refrigerant Recovery Machine. Any features to look for?

Someone posted a link on here for a home grown compressor that was used for a recovery machine. He said he liked to use an 8K system compressor.
https://www.youtube.com/watch?v=efaeYM0rpY0

If I go this route what is the best way to find a cheap compressor?

What about a recovery tank I have an old scuba tank or are there better choices like an old propane tank.

I am just looking at options if I have to do another repair I might not be as lucky as I was with this one. I might still have Freon in the system and have to do recovery before doing the repair.

What is the best way to go with this?

I use a propane tank painted appropriate EPA colors for the recovery cylinder.

A salvaged 1/2 T scroll compressor from a free CL AC unit is the compressor.

Had the 4T compressor fail on my heat pump (bearing). Recovered near 100% of R22 charge, near enough did not have to add any R-22 to get the same pressure readings after re-charging from the propane recovery cyl.

After pulling a vacuum on the cylinder, pressurize it with the system to be recovered and put it in a freezer. Most of the charge will migrate into the cylinder. Then finish it off by moving it into a cooler full of dry ice.

That's the cheapest method I have ever heard of. I have had good luck with just a bucket of ice water. Be sure to weigh the recovery cylinder before you begin. A cattle feed bucket is big enough for a BBQ tank.

cheaper
 

cooler full of dry ice.

That is lots more expensive than a free 1/2T scroll off CL and a few ounces of brazing for the fittings ::thumbup:

True. Those little pumpkin compressors in refrigerators take more abuse than the little rotary pots found in room air conditioners. They pull a pretty good vacuum as well. You can't beat free (not as an amateur anyway).

Scroll compressors don't like to be used for pumps like the old recip compressors. As for tanks they can be found at pawn shops as can recovery machines.

One caveat on using scroll (or hemetic piston) compressors for vacuum:

ONLY use 120V motor compressors, if you use 240 scroll and pull a partial vacuum the air density gets below the Paschen minimum and the motor winding will arc over to the stator and you will destroy the motor.

So a refrigerator compressor would work the best for this job.

BEST is a strong word in this subject. There are a ton of "ifs" to consider.

IF you are trying to follow lawful, federally mandated professional procedures, none of the mentioned methods apply. Go buy a DOT 40 cylinder, a UL listed recovery machine, and approved hoses and fittings with shutoff and blowoff valves everywhere. Not to mention safe handling methods trainings and the EPA card you need to possess before accessing the refrigerant loop. In this approach, safety and protocol rule over economic concerns.

OTOH, if you are a "pirate hacker idiot", then the mentioned methods will work, but you assume all of the associated risk. For R12/R22/R134/R290 systems, a compressor/condenser/fan assembly from a common upright refrigerator works wonderfully:

http://tech.akom.net/uploads/diagram...components.png

Just chop the evaporator and cap tube loose, extract the entire condensing unit assembly, and install some flow controls and fittings. If you are a savvy hacker, you can use the included bullet strainer/drier to filter the gleaned liquid on its way into your recovery cylinder. A low pressure cutout can be rigged in place of the thermostat if desired.

Welcome to the dark side. Remember to keep to the code, arrr...

Somebody told me these things make a good space heater while not being used recovering refrigerant...