First, the choice of "220V AC Cooling Fan" must be able to provide enough exhaust volume (speed), under the high temperature of the cooling device inside the hot air; when the temperature is relatively low and less when it is done thermals Conversely work. Secondly, the position of the sensor should be installed at the selected note to the sensor in the proper position, as far as possible so that the sensor can be clamped directly to the surface to be cooled. In operation, a temperature-controlled "220V AC Cooling Fan", will run at a faster rate higher if the therm temperature sensation; and at lower temperatures, it will operate at low speed; in these more intermediate high and low, fan speed will almost never due to temperature change. When "2220V AC Cooling Fan" slow temperature change, change the fan speed is slower, no sudden changes in the fan speed and noise. The reaction time mainly depends on the length of its sensor to the heat-sensing sensitivity.