I had my assistant change out a condensing unit and evap. coil yesterday. The guy is pretty new here and so far everything he has done he has been real knowledgable on. He is e.p.a. certified and all. Well, he calls me about three hours after he started and said he was having problems getting theunit charged properly. I went over and checked it over and assumed he did a proper vacuum and tests. I added some r22 and the guages read zero, did it again, zero, 3rd time, still no leaks found. Finally after 30 minutes I looked at the evap. coil and found that he didn't even hook up the highside at the coil. I won't assume he knows what he's doing next time.