1. Check LEDs: Each photo eye has a status LED. One is the sending unit, the other is the receiving unit. The receiver LED must be solid (not blinking).
  2. Loosen the brackets at the track near the floor (bottom of the vertical rails).
  3. Aim the sensors so the lenses face each other directly at the same height (typically 4 to 6 inches above the floor).
  4. Tighten the brackets while keeping alignment. A solid LED on the receiver confirms alignment.
  5. Clean the lenses with a soft cloth to remove dust and spiderwebs.

If alignment will not hold, a bracket may be bent or a sensor cracked. Consider replacing the sensors.