Garage Door Safety Sensors and Auto-Reverse

Why the rules exist

Garage doors are heavy and move with force. The U.S. Consumer Product Safety Commission documents injuries and deaths from garage doors, including children trapped under closing doors, and publishes safety guidance for homeowners (U.S. Consumer Product Safety Commission, garage doors and openers). Federal rules since the early 1990s require automatic openers to include entrapment protection.

Photo-eye sensors

The two small boxes mounted a few inches above the floor on each side of the door are photo-eye sensors. One sends an invisible beam to the other. If anything breaks the beam while the door is closing, the opener reverses. The sensors are mounted low so they catch small children and pets.

• Each sensor usually has a small light. When aligned, both lights are steady.
• A blinking or off light often means misalignment, dirt on the lens, or a wiring problem.
• Bright sun hitting a sensor can confuse it in some setups. West-facing garages in summer sometimes see this.

Contact reversal

Separate from the photo-eyes, openers are designed to reverse if the door hits something on the way down. That depends on the force and limit settings. If force is set too high, the door may push too hard before reversing.

The monthly test

The CPSC recommends testing both features regularly (U.S. Consumer Product Safety Commission, garage doors and openers):

1. Photo-eye test: start closing the door and wave an object through the beam. The door should stop and reverse.
2. Contact test: lay a piece of wood flat or a roll of paper towels on the floor in the door's path. When the door touches it, it should reverse.

If either test fails, stop using the opener until it is adjusted or repaired.

Common problems

• Door reverses for no reason: sensors bumped out of alignment, a spider web, a dirty lens, or a loose wire.
• Door will only close while holding the wall button: many openers use this as a fallback when sensors fail.
• Old opener without sensors: openers that predate the rules should be replaced.

Everyday habits

• Keep remotes away from children, and mount the wall button high.
• Do not walk or run under a moving door.
• Watch the door until it closes fully.
• Check the CPSC site for opener recalls (U.S. Consumer Product Safety Commission).

See opener repair and installation and what shapes opener work.

Related pages: garage door opener repair & installation, garage door repair, new garage door installation, and what shapes an estimate.

Sources: U.S. Consumer Product Safety Commission, garage doors and openers; U.S. Consumer Product Safety Commission.