How to Repair Central Air Conditioners Central air conditions will need some professional maintenance, but there are many minor problems that you can easily fix yourself. If your central a/c unit isn't working properly, look for the problem you're experiencing on this chart and see if it's a do-it-yourself job. 1. Check for blown fuses or tripped    circuit breakers at main entrance    panel or at separate entrance    panel; 2. Thermostat set    too high. 2. Lower thermostat setting 5°. 3. Call a professional. 1. Distribution    system out of    balance. 3. Unit too small. 3. Replace with larger unit;    2. Clean condenser coil and fins; if necessary, straighten fins. 3. Remove debris blocking condenser; cut down weeds, grass, and vines. 6. Not enough    refrigerant in system. Condenser unitturns on andoff repeatedly 1. Clean condenser coil and fins.2. Remove debris blocking condenser;