I recently had a problem of unit not cooling and was told to replace unit. The tech found that I was completely out of freon and this caused the compressor to trip. They want to do a leak check and charge the system. I would of thought finding the leak and possibly repairing it would come first. My question is, what do I do to make sure I am not getting any unnecessary replacements. The unit is 8 years old and the home is vacant. I want to rent it out but in FL, no A/C means no tenant. I live in VA so it makes it tough to get straight answers. They say I'm looking at close to $$$$$ to get it running.