Garbage disposals may occasionally get jammed when a bone or other hard object gets between the internal impeller blades and the wall 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 impeller plate. As the motor heats up, the automatic shutoff feature included in nearly all newer garbage disposals will shut off the motor entirely.
Clearing the disposal is a simple matter involving unplugging or disconnecting it, removing whatever object is causing the jam—which may require using a wrench to move the impeller assembly—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 just a few minutes.
What Are Impellers?
The impellers inside your garbage disposal are metal lugs screwed onto a metal plate. When in operation, the plate spins quickly and the food particles are thrown against the sides of a grinder ring by centrifugal force. The impellers then force the food through small openings, grinding them to extremely small particles.
You will need an Allen (hex) wrench to fit the socket on the bottom of the garbage disposal housing. Most disposals come with a little wrench just for this purpose. (It's probably somewhere at the bottom of your sink base cabinet.) If you don't have a disposal wrench, you can use a standard 1/4-inch Allen wrench.
Equipment / Tools
- 1/4-inch Allen wrench
- Needle-nose pliers (optional)
- Cold water from sink
Disconnect the Disposal
Unplug the garbage disposal unit from the outlet it is plugged into. If the unit is hardwired and has no outlet, make sure the switch controlling the disposal is in the OFF position, and then turn off the disposal's circuit breaker in your home's service panel (breaker box). This ensures that the disposal can't be turned on accidentally.
It's much better to be safe than sorry here: Triple-check that the disposal is disconnected from power and cannot be turned on accidentally before moving on to the next step. If you can't find the breaker that controls the circuit, turn off your home's main breaker, which will cut power to the entire house.
Check for Obstructions
Use a flashlight to peer down into the sink opening of the disposal. You may be able to see the object jamming the impellers. If you see an obstruction, you can attempt to remove it by hand. Alternatively, you can use needle-nose pliers if you're uncomfortable with using your hand. (There's nothing sharp inside the disposer, including the impeller lugs, which are blunt metal.)
Loosen the Jam
Identify the hex socket on the center of the underside of the garbage disposal unit. It's inside a small, round hole in the motor housing. Insert the hex wrench into this socket, and then move the wrench back and forth to free the jam or confirm that the impellers are freed. This socket is connected directly to the impeller hub, and moving the wrench usually loosens whatever object is jamming the disposal.
Plug the disposal back into the outlet, or switch the disposal's circuit breaker back on to restore power.
Reset the Disposal
Press the small reset button on the disposal unit; this is usually a red button located on the bottom of the unit. The reset button works like a circuit breaker that automatically trips to prevent the motor from overheating. Pressing the button resets the little internal breaker.
Test the Disposal
Run the cold water at the kitchen faucet, and then turn on the disposal. If it spins freely, you're done. If the motor hums but doesn't spin (and may shut itself off), it's probably still jammed. Repeat the same process to free the jam and reset the unit. If the motor won't turn on at all, it's likely that the disposal has burned out and needs to be replaced.
Choosing a New Garbage Disposal
Replacing a garbage disposal is a relatively easy project that most homeowners can tackle in a couple of hours. Choosing a new disposal that is the same size and brand as the original can save a lot of time because you won't have to reconfigure any plumbing connections. Often, it's easy to find a matching replacement because one manufacturer (InSinkErator) makes the majority of disposals in the United States.
If you feel that the old disposal was underpowered, step up to the next horsepower rating on the new unit. For most homes, however, a 3/8- or 1/2-horsepower motor offers plenty of power. Depending on the unit's quality level, garbage disposals can be expected to last from 3-10 years, on average.