So I have a 15 ton copeland scroll, on a system with about 90lbs charge. I am just re-charging it with R-438 (MO99). I charge about 70lbs as a liquid into the liquid line, just above the receiver (which is on the roof). Now, when I go down to take a look at the compressor before starting, I can see through the oil sightglass the liquid level in the compressor is over the top of the glass.

I assume I'm looking at the compressor full of liquid refrigerant under the oil. Here are my two questions:

-What do I do now to boil off that refrigerant so I can start it and add the rest of the charge?
-What can I do in the future to avoid this happening when I charge?