It may be, that you have it running in continuous mode, rather than timed mode. Also, most dehumidifiers fans will run almost continually, to keep the air moving, so the humidity sensor can pickup and increase in humidity, if there is one.|
If the above doesn't seem to be the problem with your unit, turn The Master ON/OFF Switch to OFF and unplug the unit for 12-15 minutes. This will give the electronics time to reset themselves, if necessary.
Hope this helped you to troubleshoot and solve the problem. Please let me know. Thanks.