When installing the regulating door, pay attention to whether the rotation direction of the blades of the regulating door is correct, and ensure that the direction of air intake is consistent with the rotation direction of the impeller. The common regulating door is a petal-shaped leaf-type regulating door, the regulating range is from 0 ° (fully open) to 90 ° ( fully closed). Adjust the handle position of the door so that it is on the right when viewed from the direction of the air inlet. For a right-rotating fan, push the handle from bottom to top to fully close to fully open. For the left-rotating fan, move the handle from top to bottom to fully close to fully open. Centrifugal fan rotation introduction: the fan can be made into two types of right-handed or left-handed: viewed from one end of the motor, if the impeller rotates in a clockwise direction, it is called a right-handed fan; if it rotates in a counterclockwise direction, it is called a left-handed fan.