How does the POWERFUL mode work and when does it turn off automatically?

POWERFUL mode operates the unit at maximum power and strong airflow to quickly cool down or warm up the room, and is activated by pressing the POWERFUL button (the indoor unit emits 2 short beeps). It automatically turns off when the adjusted room temperature reaches the set temperature in COOL, DRY, or HEAT mode, or after 20 minutes have passed since it was activated. POWERFUL operation cannot be used simultaneously with ECONOMY operation. (Page 4)