We had a start up on some computer room equipment. We pulled a 250 micron vaccum and held it for 20 minutes. Had a 18 degree superheat. But could not get the subcooling below 35 degrees. I know that it is not overcharged because the circuit can hold 70 pounds, and we only had 35 pounds in it. I was using new refrigerant. Could it be bad refrigerant. Has anyone ever heard of that.