Message from technicians air conditioner . Probably due to begin adjusting the low temperature and fan high level. And then adjusting fan low level with temperature to low. Thus cooling the air vent is not fully formed ice in the pipe air cooling. Solution is off the air-condition for about two hours for the ice to melt, thus opening a new aircondition. He suggested that if the air temperature is below 25 ° C requires the fan must high level.