My double garage door can open and close normally.
Suddenly yesterday the garage door can open normally as usual but won't stay close.
It will touch the bottom of the floor and then immediately open again.
A workaround is that when it touch the bottom of the floor, if I pull the red emergency release string at the right time then it will stay close.
Please help to solve the problem.
I don't know the solution but I've had the same problem, my parents had the same problem. You always have to be ready to push the button as soon as it starts to go up again. But then all of the sudden, it stops happening. Go figure!
I turn the "Down" limit adjustment screw so that the garage door will stop momentarily at 3 feet above ground (higher than the safety reversing sensors), then reverse to a fully open position. There is no visible obstruction or interference to travel cycle and no opener light is flashing. The safety reversing sensors are not obstructed.