The epa certification is not needed to buy and install a package unit.
Good luck to people trying to learn new skills when homeless and likely severely mentally ill and or addicted to drugs.
I know I couldn't do it.
LOL yes, at some point your going to have to install refrigerant if your doing it yourself on a new unit: the factory charge refrigerant may or may not match the complete system. For the newbies/laymans::: not all units are charged with refrigerant, some are nitrogen (stored)- one needs to weigh in the charge in this case from a tank of refrigerant.
**I hadnt even touched on proper EPA evacuation/recovery and re-commisioning if the OP went the repair route.
DRIVE HOME POINT #C is I think EPA 608 test should be part of 6th-7th grade science curriculum in public schools; as a former professor & teacher I compared the 608 EPA with a current science curriculum and a lot would support science concepts in this curriculum grade.
Luck has nothing to do with learning new skills. Dig deeper. Having an autistic child (mental disability) his "LUCK" has nothing to do with his will to learn a skill.
Sorry for causing the off topic digressions.