Following modes are supported by this power supply :
Mode 1: switch on unit in up position
conventional temperature control
Mode 2: switch on unit in the mid position
fan is deactivated
Mode 3: switch in down position
progressive temperature control
when the temperature reaches 64 degrees Celsius, the fan starts running automatically and it turns of by itself, when reaching the temperature of 45 degrees Celsius. In case, the power supply reaches again 64 degrees Celsius, the same procedure repeats itself.