Joke Collection Website - News headlines - There are three air vents on the top of the hotel room. How to distinguish the outlet air and the return air?

There are three air vents on the top of the hotel room. How to distinguish the outlet air and the return air?

One return air outlet, one air outlet, and one inspection opening;

When the air conditioner is turned on, the air outlet is where the wind comes out;

The one that sucks air in It is the return air outlet, and the other is the inspection opening;

If the air conditioner cannot be turned on temporarily, open the inspection opening (the one without the return air grille) and judge from the structure of the air conditioner which return air and which Out of the wind.

The generally square one is the inspection opening.