No cool on kitchen unit and living room unit. Neither thermostat had any malfunction codes upon arrival. Turned system and kitchen to cool and thermostat was stating invalid set up. I cycled power and thermostat had same issue. I made the simple correction to just to 3.5 ton unit. System came on and operated properly all day long. I went to attic to verify that all dampers were opening and closing. All of them were. System is 13 years old. From what I can gather at some point in time blower could be malfunctioning. Refrigerant level was good. So there is something going on with the electrical side of the system. Possibly the control board. But it is hard to diagnose a working board to be bad. I checked the living room area. System called properly the whole time I was there. From 2 o’clock until 630. That system seem to be operating properly as well. From my experience these two units were work the hardest from the previous homeowners. Recommendations today is to change out these two