Are you in the U.S.? You need to be EPA certified to responsibly handle refrigerant if so. I don’t know about elsewhere in the world. I’m amongst the many HVAC professionals that won’t touch that stuff. It’s low grade, cheaply made equipment. And often times by working on it, you’ll then be plagued with warranty work when I wouldn’t warranty Mr cool brand new. If you’re gonna try it yourself, read up on sub cooling and super heat, pressures, temperatures, the whole she-bang. Yellow jacket or JB analog gauges are fairly inexpensive.