Performed diagnostic. Homeowner states that unit is having intermittent issues with the unit not heating, and will display error code for no communication with indoor motor. Homeowner just replaced his Icomfort thermostat for a nest. Noticed that G terminal was not wired in at the thermostat or the unit. Went ahead and wired it in correctly on both ends. Cycled system for heating numerous times, unit kicked on normally every time. If unit still has communication error, indoor motor will have to be replaced. System is operational upon departure.