Without pump:Shut the outlet valve of the reciever and pump down.
Bypass the LP cut out.
Now vacuum creates in the Crankcase.
Crack open A and ensure no air going to crankcase.
First purge the line with oil.
Tight the nipple and continue the charging
Problems of Overcharge
Liquid may return back to compressor can lead to frosting.
High level in reciever.
HP cut out.