Thermostat "220V AC Cooling Fan" principle is: According to the elevated heat around the fan to increase the speed of the fan itself, while increasing air flow (exhaust volume). Using a thermostatically controlled fan to sense the temperature of the therm mounted on the fan hub, the fan through the sensor can detect the temperature. In the "220V AC Cooling Fan" configuration required fan is installed correctly, when the fan is installed, the therm is connected through a special wire sensors. With the fan running conditions of heat and changed to slow speed operation, "220V AC Cooling Fan" will produce less noise and consumes less energy. In most of the design requirements, the operating hours of the fan speed is lower than the air temperature is generally the maximum design temperature value. Under normal circumstances, low speed cooling fan can be enough to complete its work.