I am seeking advise on what is the right approach. I had an HVAC technician come out and replace refrigerant in one of our AC units (this was done through home warranty company). I then had another company come out that was not linked to home waranty company and had good ratings in our area, this was after an issue with the other AC Unit. The second company told me that anytime refrigerant is exchanged a drier has to be replaced as well (to prevent moisture) Now the cost of this service is ~$300 (sounds like for refrigerant exchange+drier). I called the original HVAC guy and was told that they don't change drier with refrigerant exchanges. That the reason I was told to change it is because the other company makes more money by doing services that are not necessary. So who to believe?

Came home from vacation to no A/C. I washed radiator fins, they were dirty. The compressor was warm to touch, not too hot to touch. I can turn the compressor fan blade by hand, but when energized, The fan won't come on and makes a humming, and slight vibration, then I hear compressor try to click on, fan never turns. PS, the furnace is in the attic, so the cool coil is inside the furnace, the ac radiator is outside with compressor and fan. The furnace fan works.