What is the small tube of the outlet pipe of Baojun 730 small heating tank used for?

The small tube of the outlet pipe of Baojun 730 small heating tank is used to drain water. The warm air is established by the warm air box, and the heat of the warm air box comes from the engine coolant. Warm air comes from the heat generated when the engine is working. When the cooling system of the engine radiates heat to the engine, the radiated heat is sent into the car through the fan to form warm air. The colder the warm air inside, the more water drops there will be, and the small pipes can drain water to prevent blockage.