Which would constitute the last step in a central-fan heating control sequence?
A. Hot air from the heat exchanger is delivered through ductwork by the blower to occupied spaces within the
home. When the space temperature rises above the room temperature setpoint, the burner shuts down.
B. During the heating season, when the home's air temperature drops below a predefined setpoint, the room
thermostat calls for heat and closes a switch to start the burner within the heat exchanger.
C. When the air temperature within the heat exchanger reaches the setpoint of an internal controller, the blower
motor is energized.
D. When the heat exchanger generates heat, air temperature within the heat exchanger rises. The blower isn't
operating yet.