We have a room air conditioner model RSC-3337. The compressor light indicator is on, but the air blowing from the unit is not cold and the temperature indicated on the unit has not changed from 27oC for the last 10 minutes, even though it is set to cool to 18oC. We have cleaned the filters but not sure what else to try. Is this a problem that will require a technician or can you suggest something else?