Thanks for your response.

I pulled a vacuum on the car's a/c system and immediately set the unit to charge it with virgin R134. Seven ounces were sucked in rather quickly, then nothing. The virgin cylinder seemed to be heated pretty good. I don't know how hot it should get before the pressure is high enough. The manual says it could take 10 minutes, but it was longer than that.

The car's compressor doesn't seem to be turning on. The clutch certainly isn't turning, but I can turn it by hand. Does the car's compressor need to be running in order to draw in more of the refrigerant? If so, how do I get it to run?