Question:
I have a Lift-master garage door opener (identical to Craftsman, so I've heard)
that was installed by our homebuilder.
When we try to lower the door, on occasion it'll refuse to go down all the
way and start the light to blinking.
The manual indicates that something has tripped the safety reverse infrared
beam.
I've checked & checked, but the sensor & sender are well aligned, and there's
nothing in the path. This is very frustrating, because the only way to get the
door down when it's acting this way is either manually, or stand inside the
garage and hold down the hard-wired button.
Anyone have any experience with this problem before?
Answer:
Does the manual say definitely that the infrared sensor has been tripped,
or is it possible that the force sensor tripped it? Try this experiment:
Start it lowering, stand under it (carefully), and catch it with your
hands, in order to trip the force sensor. (Alternatively, set a sawhorse
under the door and lower it.) If it trips with the same symptoms, then
I'd suspect that the rollers are jamming on one side.
