Insufficient air volume and pressure: Blockage of the pipeline system is the main reason, such as dust accumulation on the inlet filter and foreign matter accumulation in the pipeline; Unreasonable pipeline design, such as being too long or having too many bends, can also increase resistance. In addition, severe wear of the impeller, reverse rotation of the impeller, or excessive sealing clearance between the casing and the impeller can cause gas backflow, resulting in a decrease in air volume and pressure, which cannot meet the requirements of the working conditions.

Abnormal noise (pneumatic type): In addition to noise caused by mechanical vibration, airflow related noise is also common. For example, aerodynamic noise caused by turbulent airflow and eddies at the impeller; There is also a dangerous phenomenon of surge, which can cause the fan and pipeline to emit a low "wheezing" sound. This is caused by excessive resistance in the pipeline network under low flow conditions, resulting in periodic oscillations caused by gas backflow. In severe cases, it may damage the equipment structure.

Abnormal motor operation: On the one hand, overcurrent may occur due to excessive fan load, such as abnormal pipeline resistance, increased gas density, or mechanical friction between the impeller and the casing; On the other hand, it is possible that the motor cannot start or has insufficient speed, which is commonly caused by starting capacitor faults, motor winding disconnections, or unstable power supply voltage.