A garage door system can work with a single spring, but most garage doors have a two-spring system and heavier doors require more than two springs. If your garage door has a broken or damaged spring, it should not be used, especially not with an automatic opener. Garage door springs provide the force needed to counteract the weight of the door, and they are the counterweight component that rolls and unrolls when the door opens and closes. It can be a nuisance if the spring on a garage door breaks, and while it's OK to open your garage door with a broken spring, it is recommended that you contact a professional technician in garage door repair service for assistance.
If your garage door has two or more springs and only one is broken, you can open and close the door, but you should be aware of the risks. Pulling on the rail can cause the opening rail to bend due to the weight of the door, and in less common cases, the motor could fall off the roof. When a spring breaks on your garage door, you won't be able to operate it as usual. Keep the door completely level, as any tilting could deviate or at least bend the vertical rails.
Often, homeowners don't even notice that their garage door has a broken spring until something else breaks and the door doesn't work. If the cable is unwound from the drum, one side of the door will try to fall to the floor while the other side will try to stay in place. If your garage door is too heavy to move, don't put yourself in danger by trying to open it anyway. In a well-balanced door, the opener will simply have to move the door while the springs support its weight.
Using your garage door opener with a broken spring could burn out its engine since it makes the garage door heavier. The springs are normally installed on top of the garage door and they counteract its weight by rolling it up and unrolling it every time someone opens and closes it. Using your garage door when any of its components are broken or faulty may result in premature failure of its parts.