Hi, I had a new split central heat/ac unit installed a few days ago. The compressor is making a very loud humming noise. The unit is a goodman (3 ton 13 seer R22). The tech worked a very long time trying to get the unit to cool. (it was cooling just fine, I checked the air temp coming out of the vents and is was 52, so I don't know why he said it wasn't cooling). The house was cold! The noise is what I am concerned with. He came back the next day and said he had to put a hard start kit on it and a heavy duty compacitor. Also said there was too much freon in it and discharged the excess. The air temp coming out of the vents is now 60, and the unit sounds the same, loud humming noise. I am thinking it has a bad compressor, but I know nothing about a/c's. What should I do? All this work on a new unit doesn't seem right..

Thanks for any help out there!