My comments apply to the 5 button CCC and not the newer CCC2, which is a confusing bugger.
If you turn off the switch on the bottom of the CCC and hold down the top and bottom button on the face of the unit WHILE switching on the black switch on the bottom, you will see "FF" in the display until you release the buttons.
Assuming you have a heat pump and it is wired correctly, somewhere around the mid 30s* outside temp, the heat pump will switch over to the furnace automatically. In the morning or when temps rise again to that threshold, the system will switch back to heat pump.
is removed from the CCC thermostat (batt removal or shutting off the cutoff switch at the power center, the reprogramming steps must be taken for the auto switchover to work. You must be in the HP mode for this to work. When the switch to furnace occurs, you will see both "aux. heat" and "heat pump" on the LCD display.
This is explained in manual....but I can't seem to find a pdf online.