Originally Posted by
David T
I agree, R-12 is still the best choice for a refrigerant but using a sealer is a good idea too. As far as testing goes, pulling a vacuum and watching it for 30 minutes is not really a good test. It is only minus 15 psi. If you do have a leak it only draws in contaminants, won't tell you where the leak is, and can't tell you if you have a very small leak. The way to test is to fill with 150 psi Nitrogen and watch the pressure and if it drops then you look for the leak with leak detector (soapy water).