Everything You Need to Know About Garbage Disposals
The garbage disposal is mounted to the underside of a sink and is designed to collect solid food waste in a grinding chamber. When you turn on the disposal, a spinning disc, or impeller plate, turns rapidly, forcing the food waste against the outer wall of the grinding chamber. This pulverizes the food into tiny bits, which then get washed by water through holes in the chamber wall. While disposals do have two blunt metal “teeth,” called impellers, on the impeller plate, they do not have sharp blades, as is commonly believed.
Don’t Put These Items Down Your Disposal
There are a few biodegradable items that aren’t a good idea for disposals, such as:
- Fruit pits: Fruit pits are best to be deposited in your compost or garbage, not the disposal.
- Large bones: If you’re finding yourself trying to shove something in the disposal, then it’s too big. Toss big bones in the compost or trash.
- Shrimp shells: Shrimp shells are pretty tough and can also leave a not-so-fresh scent.
- Banana peels: Because they’re super fibrous, toss your banana peels in the compost instead.
- Nuts: Let’s just imagine peanut butter in your garbage disposal for a moment. Yeah, not such a good idea.
- Grease: Avoid pouring grease or anything super fatty down your drain or in your garbage disposal. It congeals into a big, nasty mass that will clog your pipes.
- Corn husks: Husks are another fibrous material that make your disposal work really hard. It’s best to toss them in the compost.
- Onion skins: Onion skins are also a no-no for the garbage disposal.
- Artichokes: The leaves of an artichoke are really tough and can get caught in the disposal blades, causing it to break down.
- Potato peels: Potatoes are really starchy, which isn’t a good combination with your garbage disposal — or your drain. Toss in the compost instead.
- Asparagus: Another fibrous veggie that isn’t good for the blades of your disposal.
- Pasta: Pasta expands in pipes, even after it’s been shredded to bits, which can cause clogs.
- Rice: Just like pasta, rice expands so avoid letting it slip into your disposal.
What Causes a Humming Garbage Disposal?
When the disposal is humming this means that it is getting power, but is not functioning properly. This is generally due to a jam.
In most cases if your garbage disposal is humming it is because a foreign object is stuck in the disposal. If an item has been jammed in the blades of the disposal they will be unable to rotate.
This can result in a humming noise. If this is the case simply unplug the disposal under the sink then survey the drain hole. If you discover that an object is stuck in the blades remove it. Once you have done this you can plug the disposal back in and flip the switch.
This should clear up the problem.
How to Replace a Garbage Disposal
Prepare for the Project
Make sure you have all parts listed on the instruction sheet. Turn off the power to the disposal at the circuit-breaker box. It’s a good idea to check the amperage of the circuit to be sure the disposal won’t overload it. The amperage should be shown on the breaker switch.
- Remove the Drain Arm and Tube
Disconnect the drain arm from the disposal unit. Use pliers to loosen the spring clamp holding the dishwasher drain tube in place. Then remove the dishwasher drain tube from the unit.
- Take Out the Disposal Unit
Remove the disposal unit by twisting it off of the mounting nut. Dump out any remaining water and debris. Turn the unit upside-down, and remove the plate covering the electrical connections. Remove the grounding screw and wire nuts, and pull the cable out of the unit. You may also have to loosen a strain relief sleeve.
Remove the existing mounting assembly and drain. Unscrew the mounting ring, and push the drain flange up through the drain hole. Scrape off any old plumber’s putty from the sink.
Note: If your new disposal is the same model as the old unit, you won’t need to replace the mounting hardware.
- Install New Hardware
Place a rubber seal on the underside of the drain flange. If your new disposal doesn’t include a rubber seal, you’ll need to use plumber’s putty. Push the drain flange into place in the drain hole.
Place another rubber seal on the drain flange on the underside of the sink. Attach the metal backup ring, flat side up. Most disposal units use metal mounting hardware, but some units use plastic. Check your owner’s manual for specific installation procedures.
- Attach the Mounting Ring
Loosely attach the mounting ring with three screws. Push the mounting ring up, and secure it with the snap ring. Tighten the mounting screws until the assembly is tight and even.
- Prepare the New Disposal
If your disposal will be connected to the dishwasher drain, use a hammer and screwdriver to remove the knock out plug. Turn the disposal upside-down, and shake it to remove anything that might be inside. Remove the electrical plate, and gently pull the electrical wires away from the unit.
Screw the strain relief sleeve into place, and push the electrical cable through the sleeve into the disposal. Firmly tighten the sleeve.
- Complete the Installation
Connect the electrical wires, splicing white to white and black to black, then secure the connections with wire nuts. Connect the ground wire to the green screw on the disposal, and replace the cover plate.
Hang the disposal by twisting it into place on the mounting nut. Rotate the disposal until it is properly aligned, then attach the drain arm and dishwasher drainpipe. Run water through the disposal for a few minutes to check for leaks. Then turn the power back on.
Note: The disposal may be heavy, so you might want to build a support base to hold it up
Garbage Disposal Maintenance
What do we mean by use it properly? We all know there are certain things that shouldn’t go down the garbage disposal. Garbage disposals are only meant for biodegradable food—you should never put anything down there like bones, plastic, or metal (such as silverware).
But even certain foods shouldn’t—ideally—be allowed to pass through the disposal, including:
- Grease and oil, which can solidify in the drain and cause clogs
- Stringy vegetables (like celery), which can get caught on the blades and cause clogs
- Rice or pasta, which expand when wet
- Fruit pits or any other hard food that can damage the blades