I live in a townhome that's four years old. when I turn on the A/C the unit cuts on but no cold air blows...just air. The fan is on Auto and lever is to cool..(checked the obvious), I have also tripped the breaker box once. What is the deal.....? Any secrets before calling a repairman? Also, my dog happens to pee on the edge of the unit some....not directly on it, but their is a little build up....but it is not going directly in the unit....Help