jamesgangnc wrote:
....
... occasionally I found the door reversing during the close
operation. After each failure, I checked for obstructions and never
could find one, much less duplicate the reversing problem. It just
happened perhaps one time in twenty!!
....
Older opens that did not have the optical obstruction sensors on the
floor often had a load sensor in the unit. There may be some
adjustors on the unit.

AFAIK still do? At least the one I just installed does; can't imagine
would design without it.

Anyway, the intermittent and the mention of the IR sensor reminded me --
had a loose piece of material hanging that occasionally would interrupt
the beam once't upon a time--took a while to realize what that problem
actually was also because it was intermittent and wouldn't perform on
demand, either...

--