When the fan is set to auto and the thermostat is closed, what voltage should ideally be present at the input side of the coil on line #11?

In a heating, ventilation, and air conditioning (HVAC) system, when the fan is set to "auto" and the thermostat is closed, there should ideally be no voltage present at the input side of the fan coil on line #11. This is because the "auto" setting means that the fan only operates in conjunction with the heating or cooling system when the thermostat calls for heating or cooling. If the thermostat is closed, it indicates that there is no demand for heating or cooling; therefore, there will be no voltage supplied to operate the fan motor, resulting in 0 volts being present on the coil's input. Understanding the function of the thermostat and fan settings is crucial in diagnosing and troubleshooting HVAC systems effectively.