I don’t have many of these and this is the first time i had this (#8) error. Tried a learn run command and now instead of re-opening four inches form close it is reopening 1 inch from close. Any recommendations (or documentation…could not find what I was looking for on the Unitec site).
Repeated tries closing the door. Sensor is fine. Buttons not stuck. Closes 90% then re-opens a dozen times then beeps non-stop. Fault code (blinks light) is #8 motor overstress.

Any recommendations would be appreciated.

Did you pull the car door gibs and look for debris? Does it do it on all floor?

Yeah. Track clean (no scrapes). Sensor responds at other positions. Doesn’t seem to be that. Don’t think it is any buttons. My rough guess is someone pushed hard on the door when it tried to close and caused a fault. If I do a reset on controller it closes. But as soon as it answers a call it gets messed up. First and second floor. Three stop hydro.
Was going to check the door close limit sensor tomorrow and try to re-learn (finally found some notes online) in case I didn’t do it right.
Only ever had a sensor error on these operators or just completely dead. Never a number 8 fault.

Is the belt tracking proper over and around the sheaves?
Have you tried to modify door closing speeds?
When on inspection mode, does closing the doors manually produce a jittery movement?
Opens/closes fine at at top floor? You didn’t specify, but are the hall door gibbs on 1 & 2 free?
Do the bell cranks pivot freely, and interlock hook is not encountering interference on the lock box on the affected floors?
And last; was the belt loose when you encountered this issue? When you turn the car onto cartop inspect, do the doors drive shut? Some states don’t allow this feature to be turned on.
Bunch of questions I know, but just listing the things that aren’t difficult to check (except #2 if you don’t have a tool).