Photo-Eye Sensors: Height, Alignment and Why Yours Keeps Failing
The two small sensors at the bottom of the track cause more service calls than anything except springs. Most are fixable in minutes.
If your door closes part-way and reverses, or will not close at all while the opener light flashes, the photo-eye sensors are the first thing to check — and there is a fair chance you can fix it yourself in five minutes.
What they are
Two small units mounted low on the vertical tracks, one either side. One transmits an infrared beam, the other receives it. If the beam is broken while the door is closing, the opener reverses. That is a federal safety requirement on every opener made since the early 1990s and it is not something to defeat.
The correct height
No more than six inches above the floor. That is the requirement, and the reason is a child or a pet lying under the door. Sensors mounted higher will let the door close on something below the beam.
Why yours is failing
In rough order of how often we find each:
- Something in the beam — a bin, a bike, a coiled hose, a snow shovel leaning against the track.
- Knocked out of alignment. A bump with a car door or a mower is enough. Both sensors have to point directly at each other.
- Dirty lenses. Dust, cobwebs, road salt film. Wipe with a soft dry cloth.
- Sun glare. Low direct sun into the receiver lens overwhelms the beam. Common in late afternoon on a west-facing garage. A small shield or sun visor on the sensor fixes it.
- Loose wiring at the sensor or at the opener terminals. Staples through the wire during installation are a classic slow failure.
- Rodent damage, especially in detached or seasonal buildings.
- A failed sensor, which is the least common of these.
How to check alignment
Both sensors have an indicator LED. Typically one shows steady when powered and the other shows steady only when it is receiving the beam — a flickering or dark receiver LED means misalignment or an obstruction. Loosen the wing nut, move the sensor slightly until the LED is steady, and retighten.
Test the reversal every month
Put a solid object — a block of wood, not your hand — in the door's path and close it. The door should reverse immediately. Also test the mechanical reversal by placing a 2x4 flat on the floor under the door: it should reverse on contact.
If those tests fail, stop using the door and call us. (423) 262-3147.
Garage door trouble in the Greeneville area?
Greggs Garage Door Services offers same-day repair and new door installation across Greene County, TN. Real people answer 24/7, and the quote is always free.
