Method for controlling an air-cooled compressor or vacuum pump device and an air-cooled compressor or vacuum pump device

A method for controlling an air-cooled compressor or vacuum pump device (1) for compressing a gas, which is provided with a motor (5) having a fixed speed, wherein the compressor or vacuum pump device (1) is provided with an air-cooled cooler (14) having a fan (15) for cooling a cooling medium that is injected into a compressor or vacuum pump element of the compressor or vacuum pump device, respectively, characterized in that the method comprises the step of switching off the fan (15) when the compressor or vacuum pump device (1) is running unloaded, and that the fan (15) is provided with a timer (27) that measures the time after the fan (15) has been switched on and in that the fan (15) is switched off or reduced in speed according to the method only if the time measured by the timer (27) is also greater than a preset value.