I don't know You USED to have actual real service valves, you could close the suction side and get some idea of whether the compressor valves were OK You might try to recover the regerant, or as much as you can, and then "rig" a fitting to your vacuum gauge force the compressor to run and that would give you some idea. You can also run it for a short time in the same way and see what it will compress for air pressure on the outlet. That is again, a matter of being able to rig appropriate fittings
So far as the pressure limits on the can, you do NOT charge into high side when running. This procedure is for initial charge. You have a vacuum on the system, and NOT powered. You simply dump liquid into the high side. This gets a lot of refrigerant in, quickly. It won't hurt anything, as the liquid goes around, through metering, through evap, and back to compressor. It will be vaporized by that time.
