The following are instructions for diagnosing and fixing the majority of problems you are likely to encounter with a garbage disposal.
Motor doesn’t even hum.
No power to the disposal. Make sure the fuse or breaker has not tripped. Also, in a new home, make sure that there is power to the outlet.Motor got too hot. If someone turned on the jammed disposal the heat from the motor trying to start will trip the thermal overload switch and shut off power to the unit. Let the disposal cool for 15 minutes and then push the red reset button on the bottom of the disposal. (you also need to fix the jam.)
Motor hums but impeller won’t move (Jammed).
Make sure the power is off to the disposal. You don’t even want to think about what could happen if it started with your hand inside!!! It’s a good rule of thumb (especially if you want to keep both of them) to make sure you are looking at the two prongs on the cord before putting your hands in the moving parts of any power equipment.
Shine a flashlight down into the unit to look for an obvious cause for the jam. Have someone with small hands put on a rubber glove and see if they can feel anything that could be causing the problem. Silverware can fall into the disposal easily, especially with a worn drain cover. It’s impressive what a disposal will do to silverware.
Use the hex wrench that came with the disposal to free the jam by putting it into the socket on the bottom center of the disposal and working it back and forth until it moves freely.
Insert a broom handle into the disposal and use it to force the impeller to turn. Keep in mind that a strong person can get a LOT of force onto a broom handle and easily damage other parts. This is a great way to turn a very stuck disposal, but not if it breaks other pipes and the sink in the process. The trick is to stick the handle in at an angle so that it catches one of the blades on the impeller. You can explore these blades with a rubber glove and your hand if you are curious. The are not sharp. Try to support the broom handle with your hands as much as possible to avoid prying the disposal loose from the sink or causing some other damage.
Clogged — water won’t drain.
Have someone with small hands reach inside and see if they can find and remove an obstruction where water is supposed to go into the drain line. Some things like banana peels can do a wonderful job of clogging things up and should never be put into a disposal.
Thread a wire, perhaps a coat hanger into the drain line and see if that will clear the problem.
Disconnect the drain line and run the hanger wire into the disposal and the line to try and clear an obstruction.
Leaks around the sink.
If water leaks from where the unit is attached to the sink, especially if someone has been messing with it trying to clear a jam or something, you will need to take the unit loose and replace the plumbers putty that seals between the sink and the disposal.
If water leaks anywhere else make sure all the drain and supply lines are tightly connected. Once again, leaks like this are more likely right after someone has been messing with the unit. If all the connections are tight, and the leak is not coming from where it is attached to the sink then it is very likely that rust and corrosion have caused the unit to fail.
Worn out covers can be replaced at a home improvement center.