Arrived onsite for communication error message on Carrier communicating thermostat. Performed diagnostic. Found all equipment functional. Did not observe any burnt or loose wiring. Contacted manufacturer support. Continued diagnosing and found outside wiring or system is causing error message. This could be bad wiring in the ground or could be a bad circuit board outside. Further diagnostic will be needed. Removed AC wires from circuit and was able to turn the heat back on.
