All garage door openers should have a safety reverse feature. If the door hits an obstruction when closing, a sensor in the motor head unit should feel the resistance, stop trying to close the door and reverse the direction of travel and open the door completely.
This safety reverse feature is hidden inside the motor unit and works separately from the safety beam that goes across the bottom of the door.
The beams are easy to test, simply pass your foot in between the two sensors while the door is closing and if the door goes back up you know that they are working properly.
But that’s not what this article is about. This is about testing the internal sensor and that requires actually obstructing the travel of the door by placing something in it’s path and letting the door hit it.
If you have the owners manual you should refer to if for the manufacturers recommendation on testing the reverse, but most of them do it this way anyway.
Testing the reverse
Get a 2×4 piece of wood and lay it on the ground in the center of the door on it’s edge. Push the button and let the door close down and hit the wood and prey that it doesn’t damage the door. Try not to break the glass in the top section doing this test.
If the door continues to close after contact with the wood, you have a dangerous door and someone could be trapped or killed if the door were to come down on a person.
If the door hits the obstructing, pushes against it with gentile pressure and then reverses, you will know that it’s safe. That’s what it should do.
If you determine that the opener is not reversing properly you will need to adjust the force settings on the motorhead.