Article courtesy of Pillar to Post Home Inspections
Your garage vehicle door may be the largest moving object in your home and could weigh up to 400 pounds. For your safety make sure it’s in good condition.
Overhead garage doors have gravity to deal with. In the absence of some type of balancing mechanism, the door would slam shut as soon as you let go of it. Older garage doors may employ a weight and pulley system to balance the weight of the door however virtually all modern systems use springs. Regardless of the method used, the door should balance. If you open the garage door about half way and let go, it should balance there.
The springs used to balance the weight of the door are under enormous stress. If a spring were to break, flying pieces of metal could cause serious injury. Modern spring systems incorporate safety features to prevent flying metal in the event of a spring failure. For example, extension springs should have a cable running down the middle of the spring to contain the spring upon failure.
Automatic door openers are not a replacement for a properly balanced door. The opener is normally not powerful enough to lift the entire weight of the door. The opener works with the help of the springs or counter balance system. An automatic garage door opener should stop and reverse on meeting an obstruction. Many systems manufactured prior to 1982 may stop but not reverse. These older systems should be upgraded. This is not only about protecting your car, it’s about protecting people.
Today, some form of external entrapment protection is required. An electric eye is the most common system used. The electric eye is mounted 5 to 6 inches off the floor and senses objects in its path. If your garage door opener does not have an electric eye system, you may be able to upgrade it without replacing the entire system.
During a power failure the garage door may be impossible to open. Since 1982, automatic garage door openers have an emergency release to disengage the garage door from the opener. Once disengaged, you can open the door by hand. Make sure you know where this is and how to operate it. It is usually a short rope hanging from the unit. Pulling the rope disengages the door from the automatic door opening mechanism.