Regular "220V Cooling Fan" to check if the fan is unstable found abnormal noise or vibration occurs in the action, you need the fan removed, check whether it is caused due to loose blades or "220V Cooling Fan" Bearing abrasion, we only need to be fixed blades and strong convergence ministries after you can solve the problem. Although not a big problem, but if the long-term are loose, it will cause more serious damage or accidents. Then, usually pay attention to the sound of the fans in watching the work, if it is noise, consider whether it is connected to the fan bearings lubricated enough, if this is the case the noise, in a timely manner to "220V Cooling Fan" bearing lubrication can regularly check fan bearing lubrication is necessary.