The PS4 has a power indicator light on the top of the system. Depending on what is occurring, it will light up different colors.
Indicator Lights compared - CUH-1200 above - CUH-1000 below
|Lights up blue then white||Powering on|
|Lights up white||Powered on|
|Lights up orange||Standby mode|
|Blinks red||The PS4 is overheating.|
You should turn off the system, move it to a well-ventilated area, and wait until it has cooled down to use it