Garbage disposals may from time to time get jammed up when a bone or other hard object gets between the internal impeller blades and the walls of the disposal. When a jam initially occurs, you will continue to hear a humming sound as the motor strains against the foreign object, jamming the blades of the impeller. As the motor heats up, the automatic shutoff feature included in nearly all newer garbage disposals will shut off the motor entirely.
Unjamming the disposal is a simple matter involving removing whatever object is causing the jam—which may require using a wrench to move the impeller blades to free whatever is jamming—and then resetting the motor using the reset button. Only the very oldest garbage disposals do not have a reset feature. It's an easy task that should take 15 minutes.
- Hex wrench to fit the socket on the bottom of the garbage disposal housing (most units come with the wrench; if you've misplaced yours, an ordinary Allen wrench will work).
- First, unplug the garbage disposer unit from the outlet it is plugged into. If the unit is hardwired and has no outlet, make sure the switch is in the OFF position.
- Use a flashlight to peer down into the drain opening. You may be able to see the object jamming the blades. More than one disposal has jammed because a spoon or other household item has accidentally gone down the drain. If possible, remove the object. If you cannot budge the item, go to the next step. (Note: Don't use your fingers to reach down into a garbage disposal. It's a myth popularized in horror movies that garbage disposals have razor sharp blades that can chew off entire hands. They have rather blunt blades intended to break up food items, not slice them to ribbons. But should the disposal accidentally start up while your fingers are inside the sink drain, a nasty injury is possible. Instead, use a broom handle or wooden spoon to try to dislodge whatever is jamming the impeller.)
- Identify the hex socket on the center of the underside of the garbage disposal unit. Insert the hex wrench into this socket and work it back and forth. This socket is connected directly to the impeller hub and moving the wrench usually loosens whatever object is jamming the disposal.
- Once the unit is spinning freely, plug the disposal back into the outlet, and press the reset button—usually a red button on the bottom of the unit. Now test the unit while running a lot of water through the drain.
If the garbage disposal fails to work even after unjamming it and resetting the motor, it's possible the disposal has burned out. If this is the case, it is time to replace the garbage disposal. Depending on the quality level of the unit, garbage disposals can be expected to last from 3 to 10 years on average.