How do I test a garage door opener?

expert EXPERT April 26, 2007

Residential automatic garage door openers come in a few varieties, but all are basically electric motors (commonly 1 .3 or 1 .2 horsepower) powering a drive mechanism.

Most drive mechanisms consists of a sprocket pulling a chain attached to a car.

The car is the device that connects to the door, usually by a steel arm. The car slides back and forth on the shaft between the opener and the wall over the door.

Some motors rotate a threaded shaft, moving the car with a gear.

An automatic opener becomes a problem when it breaks, or if the electricity is off. To open the garage door, it must be disconnected from the opener. Usually the arm is connected to the car via a spring loaded key that fits into the car. A cord and handle is provided so that, when necessary, the cord can be pulled, disengaging the arm from the car.

This is simple if access to the garage is available through a man door. If the garage is only accessible through the vehicle door (similar to a vault) then a steel cord is run from the opener disengagement to a keyed lock in the face of the vehicle door. From the outside, a key can be used to unlock the barrel, which allows it to be removed. This pulls on the cord, disengaging the opener.

Auto Reverse All automatic door openers must have the ability to sense when the door has hit an obstruction on the way down, stop descending, then automatically reverse direction. This is not to prevent damage to car hoods or bumpers. It is to prevent the door from crushing or pinning a child, pet, or fallen adult. It is not enough that the opener stop the door on its way down. It must bring the door back up.

The opener must also sense an obstruction when it is opening the door. This is to prevent crushing people standing on ladders to get to their storage shelving. This isn't as likely as a child running under a closing door, but it still represents a hazard. In this case, the door should stop only it should not start descending.

Electric operators may not work properly as a result of

• poor door adjustment or maintenance
• poor operator adjustment or maintenance
• poor installation
• a defective opener
• a loss of electric power

No access into the garage is an obvious implication. Injury may result if the garage door is very stiff to move or comes down quickly, or if the opener or door becomes detached. Missing or defective automatic reversing mechanisms are safety hazards.

Testing Garage Door Openers Look to see how the electrical supply to the openers is arranged. Some jurisdictions are very strict about not allowing extension cords to power garage door operators. This means that an electrical receptacle has to be provided close to the opener. Some jurisdictions require receptacles in garages to be on GFCIs (Ground Fault Circuit Interrupters). Find out what is required in your area.

Look to make sure that the opener is securely installed before operating it. We recommend that you stand inside the garage while testing the opener in case the door closes and cannot be reopened. From inside the garage, you can disconnect the opener and operate the garage door manually. If a problem occurs when you're standing outside the garage, there's nothing you can do about it. Also, if the push button is in the garage, once you close the door you may not be able to get in to activate the button again or disconnect a defective door operator.

It is not wise to test an automatic door opener if there is a vehicle parked in the garage under the opener. Poorly adjusted or defective openers may fall, causing damage to vehicles or injury. In some circumstances, openers can cause doors to come off their tracks. Do not stand directly below the door or opener while it is operating.

Operate the door once, paying attention to how smoothly it moves and where it stops. If the door bounces off the garage floor when closing, or stops two inches short of the garage floor, there is an adjustment problem on the closing limit, and you should get this repaired. When the garage door opens, it should not reduce the height of the door opening.

Look for buckling tubes or shafts on chain-driven openers. This may indicate poor adjustment or a defective unit. Many opener kits sold to homeowners have shafts that are thin-walled tubes, packaged in sections. The joints in the sections can be hinge points when under stress, and can buckle. Watch for chains slipping on the sprocket, which may indicate worn sprocket teeth, a loose chain, or an unbalanced door.

Many garage door openers do not automatically reverse properly because the sensitivity adjustment is set too low to overcome a door that does not move freely. If the door stops for no apparent reason and stays in place or reverses, the auto-reverse sensitivity may be set too high. It is more likely, however, that the door itself requires adjustment.

Once the door has been tested once, the automatic reverse features should be tested. This test can be done with a roll of paper towel, toilet paper or a two-inch wood block put on the ground, near the center of the door. Many people test garage doors by grabbing them at waist height. Depending on the door opener, some will reverse at waist height, but will not reverse when they get down close to the ground level. It is close to ground level where a child may be pinned, and it's here the reverse mechanism is most important.

It is possible to brake automatic openers while testing the auto reverse. If the unit doesn't stop, the stress generated while the motor tries to push against the obstruction can break something. Keep your hand on the disconnect cord pull it if the unit doesn't stop right away.

When testing auto reversing features, you should note that most doors automatically override their self-reversing feature in the last inch of travel. This is to compensate for uneven garage floors and/or snow or ice on the floor. That's why a two-inch block is used to test the door. All modern operators have an auto reverse. Some older units only stop if they meet an obstruction. A door that stops but does not reverse can trap someone under the door. If the door stops but does not reverse, we recommend repair or replacement.

As we discussed earlier, garage door openers should stop if they hit an obstruction when opening so that people on ladders don't get pinned against rafters, for example.

Many doors also have an automatic reverse feature that is based on time. If it takes more than 25 seconds, for example, from the start of the closing cycle to the end, the door may automatically reverse. This is a backup system to the automatic reverse on sensing an obstruction. It should be understood that weather changes may affect the operation of wood or metal doors as they expand and contract. Most manufacturers recommend monthly testing of garage door openers.

In many jurisdictions, new garage door openers have a photoelectric eye that senses obstructions. The eye looks across the full width of the opening. If such a device is in place, you can test the auto reverse mechanism by breaking the continuity of the beam. This beam is usually located within 12 inches of the floor.

Check that the opener can be disengaged from the door in the event of problems. The pull cord should be long enough to reach. A vault-type garage should have a keyed disconnect cord. Do you have the key for the disconnect cord? It's an easy key to lose.