Failure during operation

No. The fan setting simply runs the fan full time bypassing the thermostat. In cooling mode the unit is slave to the thermostatic sensor located in the return air stream. If the unit is in a very small room or the exiting cool air is obstructed by furniture or curtains then the cool air is directed directly back to the sensor before mixing with the room air, causing erratic operation. Be sure several square feet of floor space is open in front of the unit and point the vent upwards and see if that makes a difference. Hope this was somewhat helpful, GL.