Reason 1: The contact between the negative pressure fan and the window frame is too tight when the negative pressure fan is installed, so that the window frame resonance is caused when the negative pressure fan is running.
Solution: appropriately reduce the stuffing between the window frame and the water and air conditioner, and use a softer material to fill it. If the bottom of the installation is not stable, the bottom plate should be stabilized, and the installation should be stable and firm.

Reason 2: The installation of the negative pressure fan is poor, the installation of the negative pressure fan should be in a suspended state, and the spring of the foot bolt cannot be pressed to death.
Solution: Ask the maintenance personnel to adjust the installation state of the negative pressure fan so that it is in a suspended state.

Reason 3: The vibration damping pad or fixing screw of the negative pressure fan base is too tight, and the vibration damping effect is lost, and vibration sound is generated during operation.
Solution: Adjust the screw tightness of the vibration damping pad of the negative pressure fan base to make the base surface flat.

Reason 4: The power supply voltage is too low, and abnormal noise and vibration are generated when the negative pressure fan starts or runs.
Solution: Control the power supply voltage within the rated voltage range. Usually a voltage regulator or power regulator can be used to stabilize the voltage.??

Reason 5: The blades of the negative pressure fan collide with the fan casing (cover).
Solution: Replace the motor bearing of the negative pressure fan and fasten the screws on the base and shaft of the axial flow fan. Adjust the distance between the blade tip and the cover according to the production technical requirements, generally not more than 1.5% of the blade length.

Reason 6: The base screw of the negative pressure fan is loose, the impeller is poorly assembled, the speed is too fast, the fixing screw on the shaft is loose, etc.
Solution: Fasten the screws on the fan base and shaft of the negative pressure fan. Reassemble and adjust impeller clearance according to technical requirements

The above is the solution to the noise of the negative pressure fan, I hope it can be helpful to everyone.