you gotta troubleshoot it
First you need to eliminate the
door operator itself as the problem.
Once you do that, go looking at your equipment.
My PLC has a relay inside for 'entry
door close'.
When I had this same problem, I first eliminated the operator as the problem thru testing.
Then I looked at relays.
Then I looked at temp sensor.
Then I looked at 'emergency exit' button (customer can press if trapped in my bay and both
doors open). This switch had corroded so severely that the contacts for entry
door were 'making' from corrosion. Removed switch from circuit and problem solved.
I suggest a troubleshooting and maintenance log. This helps you remember what you tried, what worked and didn't and what parts you replaced. Many problems come back later on and the log helps solve them more quickly and easily than trying to remember everything.
Good luck!