Almost any problem you find with an inoperable unit will require professional service from Clear Comfort. We do have some suggestions as to things you can check. Check your breakers and make sure they are not tripped (toggled between the off and on position) or turned off. Check to see if there is water in your auxiliary pan under the indoor unit. Some of these problems are addressed in the following questions; “What are some causes of my breaker for my A/C unit being tripped?” “Why is there water in the pan under my indoor unit?”