Under "220V Cooling Fan" in the case of slow temperature changes, the fan speed changes relatively slowly, not suddenly change the fan speed and noise. The reaction time depends mainly on the length of its heat-sensing sensor sensitivity. Position sensors installed on the selection should pay attention to the sensor in the proper position, try to "220V Cooling Fan" sensor can be directly clamped surface to be cooled. In operation, a temperature-controlled fan will run at a faster pace if the thermistor feel higher temperatures; and at a lower temperature, it will operate at low speed; in these higher and lower intermediate, "220V Cooling Fan" will hardly speed due to temperature change.