That's my problem. I can't seem to find a reputable company in my area. I don't pretend to know enough to even attempt to fix it myself. I'm just looking for some clues to pass the info on to the latest company that has been to my home. They told me that the system is working as designed which obviously is incorrect.
Yes, the problem was fixed about a week after that post. The replaced the wiring harness and defrost board and if relative humidity is low, it will run up to 6 hours without defrosting. Ask your company to replace both of those to see if it works. Good luck!