What does it mean when 'Cool On' or 'Heat On' is flashing on the screen?

A flashing 'Cool On' or 'Heat On' message means the built-in compressor protection feature is engaged. The thermostat forces the compressor to wait a few minutes before restarting to prevent damage to the heating or cooling system. This message is also displayed during a startup delay if AC power loss occurs. Once the wait period is over, the compressor will turn back on automatically. (Page 9)