How to Replace a Garbage Disposal
The idea of installing or replacing a garbage disposal might seem daunting, but it is a straightforward job that often can be completed in under an hour – even if you do not have any prior plumbing experience. Before getting started, you should carefully review the manufacturer’s installation instructions that come with your garbage disposal for more detailed instructions.
Here is a general overview on how to install a garbage disposal:
Step 1: Remove the Drain Lines and Turn Off the Power
The first step to installing / replacing a garbage disposal is to examine the space beneath your sink to make sure that there is enough room to install a garbage disposal. If so, then you should access the breaker to turn the power off. Any existing drain lines should be removed. In order to prevent leakage, stuff an old rag in the main drain.
Next, loosen the oversized nut at the sink flange’s base and allow it to drop down. Push the strainer upwards through the sink, and remove it.
Step 2: Remove the Plumber’s Putty and Loosen Its Screws
A screwdriver should be used to carefully remove all of the old plumber’s putty from around the opening of the sink. A rag can be used to make sure that no putty reside is left behind and that the sink opening is clean. Flip your mounting assembly over and use a combination of your fingers and a screwdriver to loosen each of the mounting bolts until you have access to its snap ring.
Step 3: Remove the Unit’s Snap Ring
A flat head screwdriver can be used to gently pry the snap ring off of the sink flange. Now, the mounting assembly should easily come apart. All of the parts of the mounting assembly should now be separated. While you are doing all of this, be careful not to damage the fiber gasket.
Step 4: Apply Plumber’s Putty
A generous amount of plumber’s putty should be rolled around the sink opening. Using your fingers, press it firmly into place. The fiber gasket and the metal backup ring should then be slipped over the sink flange.
Step 5: Place the Mounting Ring Over the Sink Flange
You will need to use one hand to support the backup ring and fiber gasket in place, while you use the other hand to slip the mounting ring over the sink flange. The mounting ring should sit flush against the backup ring. A wide rubber band should be placed around the flange to ensure that all of the components are held in place. Be careful to ensure that the rubber band is placed above the snap ring groove.
Step 6: Installing the Snap Ring
The snap ring can now be installed by sliding it up the flange until it simply pops into place.
On a side note, you can now remove the rubber band, and if any plumber’s putty accidentally oozes out of the flange, it should be cleaned up.
Step 7: Push the Plug
Before you connect the dishwasher hose to the garbage disposal, don’t forget to remove the plug. Place the garbage disposal on its side, and use a flat headed screwdriver to push the plug until it moves down inside the unit.
Step 8: Remove the Plug
Now, it’s time to retrieve the plug. Sitting your garbage disposal upright, remove the gasket and its ring. Turn your garbage disposal upside down, and remove the plug from inside the disposal. After retrieving the plug, you can replace the gasket and its ring. Find the electrical hole, and insert one wire clamp.
Step 9: Removing the Cover of the Access Hole
Before touching any of the electrical wires, you need to ensure that the power has been turned off.
On the bottom of your garbage disposal, there will be a screw that holds the cover of the access hole in place. You should remove this screw, remove the cover itself, and then pull out the garbage disposal’s wires.
Step 10: Connect the Wires and Secure Them
The electrical wire should now be placed into the wire clamp that you installed earlier. After being placed in the access hole, the white wire should be connected to the other white wire, while the two black wires are connected to one another.
Wire nuts should be used to secure the wires together. You can also use electrical tape to attach the wires to the wire nuts. Next, you should hookup the ground wire.
Step 11: Place the Wires Inside the Access Hole
After all of the wires have been hooked up, the wires should be pushed up into the access hole. Replace the cover, and use a screw to secure it. The electrical clamp should then be tightened down.
Step 12: Mounting the Garbage Disposal
You may need a partner to assist you with the mounting.
The garbage disposal system should be lifted up, and the top end of the mounting gasket should be inserted into the mounting assembly. The lower mounting ring should be turned clockwise until the mounting tabs begin to feel tight and secure. If needed, adjustable pliers can be employed to lock the tabs over the ridges.
Step 13: Installing the Drain Lines
The first step for installing the drain lines will be to attach the P-tap to the trap arm and tailpiece. The discharge tube should be inserted into the T fitting. The slip nut should not be tightened all the way just yet. The other end of the discharge system should now be inserted into the garbage disposal system.
Now a screwdriver can be used on the supplied bolt to secure the flange. All of the slip nuts can now be tightened.
Step 14: Finishing the Installation
The disposal system’s bell should be slid over the disposal drain, and the clamp should be tightened up with a screwdriver.
The steps above should work (in most cases) if you are installing new or a replacing your current garbage disposal. If you were to hire a plumbing, the cost to put in a new disposal can be pretty high, so try doing it yourself first, it's a pretty easy job for most people.
I also found this video from Home Depot the first time I replaced my disposal:
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