Today I arrived on site to address a control board and Nest thermostat malfunction. Service Actions: Identified a malfunctioning control board and Nest thermostat. Replaced both the control board and Nest thermostat. Confirmed resolution of the issue. Upon arrival at the property. I explained to the client the reason for this visit. The customer was waiting for us. I proceeded to verify the system. I proceeded to disassemble the defective control board of the unit. I proceeded to install the new control board in the unit. I made all the connections and adjustments necessary to conclude with the installation of the new control board. I tore the unit. The unit began to present a failure related to the Nest thermostat. I checked the Nest thermostat, I found a malfunction of the Nest thermostat which caused the existing boar control to fail. I explained the situation to the client and suggested that the client install a new Honeywell T6 tstat. The customer asked some questions