If the A/C compressor clutch engages then you have pressure in the system, if it has been sealed it should not need a charge, I would run it for a few days to lubricate and use the system, would not recommend re charging it yourself, if you hook up to the high pressure hose instead of the low pressure hose you could do serious bodily injury, take it to a professional and let them charge and test for leaks

__________________
Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles