Automotive Vacuum Pumps for AC use
Good idea using r-12 as a flush back in the 1970's, when it was dirt cheap. By the way, have heard that ebay no longer allows the sale of r12. Can anyone confirm this.
R12/22 are fully regulated. R134, unless it has changed, is available in small cans at ridiculous prices, and anything else is regulated, and THAT has become complicated because of the different license classes. I was actually thinking of getting re-certified after all these years to have access, at least, to R410a but I got mired in a mess of regulations and idiocy.
When I first got into HVAC/R sometime in the 80s, there was no regulation, yet, but it was being talked about. It was still done, in some cases, to just dump an R12 or 22 charge in order to change a compressor.
The tiny outfit I worked for, built several dehumidifier lumber dry kilns. Imagine a gigantic window air conditioner. Some of these used 80 hp shaft drive carrier V8 compressors, two of them used I think, 60 hp Micom shaft drive, screw compressors. One of them, the head mechanic improperly installed the suction tubing, which (I forget) was 2" or so copper, and the thermal expansion broke a joint open and DUMPED 250 POUNDS of R12. Back then it only cost the shop somewhere around 1.00-1.30 or so a pound.
