10. Contact Reversal Test
UL 325 requires this test, but in some rare cases, this test has damaged the door system when the opener’s force setting has been improperly set, or when the opener reinforcement bracket is not securely or appropriately attached to the top section. If you have any concerns that this test may cause damage, a trained door systems technician should check the entire system and conduct the test.
Open the door. Under the center of the door, place a 2x4 flat on the floor in the path of the door. Standing inside the garage but safely away from the path of the door, use the remote control or wall button to close the door. When the door contacts the wood, the door should automatically reverse direction and return to the fully-open position.
In the usually rare event the NC sensors are somewhere between the 1"-2" mark above the floor. What would be an acceptable method for placing the 2x4 in the path of the door for the Contact Reversal test?
Would it be acceptable to raise the 2x4 above the NC sensors "Line of Sight" by placing a small block under each end of the 2x4?
I have only seen NC sensors that low once, usually they are somewhere in the 2.5" to 6" range.