Cleaning of the sensors and periodical testing of their response should be on your house maintenance schedule list.
A single pair of the garage door sensors includes a transmitter that emits an infrared beam and a receiver. In order to operate effectively, both of them must be properly aligned – the receiver eye must see the transmitter eye.
Each of the garage door sensors has a small “status” light that stays ON at all times on the transmitter side, and turns ON at the receiver side only if there’s a clear path between them. You might also have a receiver with a light that instead of turning OFF changes color to red or starts blinking when the infrared beam is broken.
You should install each of the overhead door opener safety eyes (top of the lens) no higher than 6” from the garage floor surface. This is critical for small children or any individual lying down on the garage floor in the path of a closing garage door.
I would not recommend installing the photoelectric garage door sensors very close to the floor surface.
Under no circumstances should you install the garage door sensors anywhere else. Sometimes I see them taped together on top of the garage door opener or secured to the roof/ wall framing, which creates a serious safety hazard – do not do it!
Things to investigate
If there’s no status light on either of the garage door sensors, make sure that the wires at the garage door opener terminals and at the sensors (if not permanently attached) are secured / wiggle them slightly to see if none of them have separated / broken at the screw that is holding them.
If none of the above helps to correct the garage door closing, you may need to call a professional to investigate the problem.
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This article was written by Dariusz Rudnicki
I'm a retired Illinois home inspector, founder and editor of checkthishouse.com, a blog which attracts around 2 thousand readers daily and is dedicated to answering the many questions of home owners and home buyers. Connect with me on Google+ Find me on Google+ Local