I had problems with my rental unit last summer. There was a leak and it was topped up. It seemed ok for the remainder of the summer. This year, the first hot day it ran and didn't cool. Coolant was added and it worked ok for a couple of days. At the beginng of June, it ran and the temperature went up instead of down. Coolant was added, and it ran ok for a day then became a fan again. The A coil has been replaced and lo an behold, it failed again. Zero coolant again. This time I was told the pipe and condenser need to be replaced. I have been waiting since Tuesday morning for a call to actually fix the unit.