[Just One More]

Sounds a bit sketchy to me. Get a tire valve tool and check tightness of the schraeder valves. Hook up pump and gauges. Any pressure from exist refrigerant?

If not pull vacuum, shut down pump and wait an hour to see if line leaks. If no leak, you will still need to get freon weighed in, check electrical and running pressure should be about 120 on the low side on a 95 degree day.

If there is pressure when you hook up the gauges, I would check electrical then consider changing out the freon. If not I would probably do as the other gentleman suggested and put a dryer inline.

Best wishes for you, your project, and your child's future drawings.

PS: Don't forget to clean your coils!