Your system is pretty simple in that it pressurizes refrigerant, reduces the pressure and removes heat. In doing this the refrigerant changes from a gas to liquid and back and fans remove heat inside the coach and other fans remove more heat in front of your radiator. Some refrigerants are more efficient than others but that is another very long discussion.
If you take the air hose from your compressor and blow air toward your hand it feels cool. This is the same rapid reduction in pressure in it's simplest form.
You need to get a 134a manifold gauge set (because you have 134a in the system) and check the system to see if you are making pressure on the high side and reducing pressure on the low side. If not then you can troubleshoot the system to find the problem.
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