Does the door still stop? Testing a garage door's two safety systems

Most garage doors around DeKalb close without complaint. The builder openers in the 1990s and 2000s subdivisions have run the same route thousands of times, and the opener in a detached alley garage may be older than the car parked under it. Closing was never in doubt. Stopping is the question, and a door can keep doing the first for years after it has quietly lost the second.

Does a garage door have to stop if something is under it?

Yes, if the opener is new enough. Under the federal Consumer Product Safety Improvement Act of 1990, residential openers made after January 1, 1991 must reverse on contact with an obstruction. Openers made after January 1, 1993 must also carry external entrapment protection, photo eyes or a sensing edge, under UL 325. When either one fails, garage door opener repair starts with knowing which.

The two systems share almost nothing. The photo eyes watch the opening and stop the door before it touches anything. The contact reverse lives in the opener head and reads resistance through the motor, and it is the backstop for whatever the beam misses: a toy sitting above the beam, a ball that rolled in after the door passed it. Because they work independently, a door can pass one test and fail the other. Run both.

How do you test the garage door photo eyes?

Start the door closing from fully open, then break the beam near the floor with an object you don’t mind losing, like a cardboard box or an empty bucket. A passing door stops and goes back up right away, often with a flash of the opener light or a click from the head. Never use a hand or a foot for this.

1. Open the door all the way and clear the opening.
2. Stand off to one side with the box, and send the door down from the wall button.
3. Once the door is partway down, set the box on the floor in line with the two sensors.
4. Watch. The door should stop and reverse without touching the box.
5. Pull the box out, let the door close, and repeat from the other side of the opening.

Where you break the beam matters. UL 325 requires the beam to run no higher than 6 inches above the floor, which puts it where a crawling child or a dog stretched across the threshold would be. Waving an arm through the opening at waist height tells you nothing about that beam.

Look at where your eyes are mounted while you’re down there. Sensors sitting up at knee height usually got moved by someone, often to keep a snowblower or a trash bin from knocking them, and that is worth fixing before anything else here. If the door refuses to close at all rather than ignoring the box, that is a different problem, and our guide to a door that won’t close covers it.

How do you test the contact reverse?

Lay a flat 2x4 on the floor across the middle of the opening, or a roll of paper towels on its side, and close the door onto it. The door should touch the object and reverse. If it stalls on it or crushes the roll flat, the contact reverse has failed, and the opener shouldn’t be used until the setting is corrected.

1. With the door open, lay the board flat (not on edge) where the door lands, centered in the opening.
2. Close the door from the wall button and take your hand off the button.
3. Watch the moment of contact. A pass is the door touching the board and heading back up.
4. A fail is the door stopping on the board and staying there, or pushing down hard enough to flex the bottom section.
5. Remove the board and close the door normally.

A board lying flat sits under the photo-eye beam, which is the point. This test is about the case where the eyes never saw anything. The paper towel roll is gentler on everything involved, and it keeps a record: a roll that comes out flattened on one side shows you how hard the door leaned before it gave up.

If the door pushes through, leave it closed and unplug the opener until the force is set. A door that will crush a board will crush anything else the beam misses.

The door reversed, but late or lazily. Is that a pass?

Not a clean one. The federal rule counts from the moment of contact and gives the opener very little time to start back up. A door that sits on the board, strains, and then drifts upward met the test by a thin margin, and in an unheated garage that margin usually shrinks when the weather turns cold.

A slow reverse means the opener needed more resistance than it should have before deciding something was there. Either the close force has been set higher than the door needs, or the door has started asking for more force to move. Both are service items. A borderline result belongs on the next tune-up, the balance, lube and safety check that runs $89 to $129 on our price list.

Run it twice before deciding. A door that reverses crisply the second time still deserves a look. One that gets slower does not wait.

What does a failed contact reverse say about the door?

Often that the opener is the innocent party. The close force may have been wound up by whoever adjusted it last, usually to stop a stiff door from reversing on its own in January. Or the door has gotten heavier to move, and the commonest reason is a spring near the end of its life that no longer carries its share of the weight. The opener makes up the difference by pushing harder, and a motor pushing that hard can’t tell a heavy door from a child’s bike. Before anyone turns the force back down, the door’s balance needs checking. If the spring is the cause, garage door spring repair comes first, because resetting the force on a door with a failing spring hides the problem until the spring breaks.

What if the opener has no photo eyes at all?

Then it almost certainly predates the January 1, 1993 requirement, and the contact reverse is the only thing standing between the door and whatever is under it, assuming that still works. For a household with small children or pets, or a rental with tenants you’ve never met, that is the case for a new opener rather than a repair.

We don’t recommend bolting a sensor kit onto an opener that was never built to read one. A new opener, installed, comes with its sensor pair, and our opener repair and replacement page lays out the installed options.

How often is this worth running, and who runs it on a rental?

Twice a year covers most homes, once before the cold sets in and once in spring. Add a run any time the opener has been worked on or the door has taken a bump from a car, since either can move the setting or the sensors.

On a rental, both tests belong in the walk-through between tenants, when the garage is empty and nobody is standing in the doorway. Our rental garage door guide covers that check. With most leases near NIU turning over in August, one of the two yearly runs schedules itself. If either test fails and you’d rather not guess at the setting, a failed reverse is a standard garage door opener repair visit, and a quick one when the door itself is sound.