Both products require maintenance and upkeep during use in order to extend their lifespan and prevent malfunctions. Of course, it has good ventilationsuction fan No exception. Although the quality of Litong ventilation fans is good, good things also need to be used properly and taken care of in order to achieve the desired effect. Litong ventilation fans are no exception. The daily maintenance of the negative pressure fan requires the following points: 1. Regularly check whether the screws on the fan motor frame and other parts are loose. 2. Regularly check whether the screws on the fan blades are loose. 3. Check whether the fan motor is running well, whether it is slowing down, whether there is buffering start, whether there is excessive noise, etc. 4. Check whether the control fan switch is stable and keep the circuit in good condition. 5 Check if the voltage is stable and keep the circuit in good condition Keep the fan clean