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One of the handiest appliances in your kitchen is probably something you don’t think about very often, until it stops working. It’s your garbage disposer. In this video we’ll show you how to replace a garbage disposer. This project requires some moderate do-it-yourself skills and some basic knowledge of electrical wiring.
One of the handiest appliances in your kitchen is probably something that you don’t think about very often, until it stops working. It’s your garbage disposer, and today I’m going to show you how to replace a garbage disposer under your kitchen sink. This project requires some moderate do-it-yourself skills, and it also requires turning off the electricity to the disposer at the electrical panel. But it’s really not that difficult, so let’s get started.
First, we’ll remove the old disposer. Start by disconnecting the drain trap from the disposer’s discharge tube. You’ll also need to disconnect the slip fittings to the drain, and the dishwasher inlet hose, if your dishwasher drains through your disposer.
Now it’s time to disconnect the old disposer from the sink. Support the disposer so it doesn’t fall, then insert a screwdriver into the right side of the mounting lug and carefully turn it clockwise. Some manufacturers supply a wrench for this purpose.
Flip the disposer over and unscrew the electrical cover plate on the bottom of the disposer by removing the cover plate screw. Again, be sure the power to the unit has been turned off at the electrical supply panel. Then disconnect the electrical cable connector. Pull out the wires and remove the wire nuts. Also unscrew the ground wire from the green ground screw. Be sure to save the electrical cable connector so you can use it again.
After you have removed the old unit, you have a couple options that you might consider. Some manufacturers’ disposers can use the same mounting ring, which makes installation a lot easier. However, today we’re going to show you how to install the mounting assembly in case yours is a new installation or a brand that is different from old disposer.
This part of the installation starts by removing the old mounting ring by loosening the mounting screws and then removing the snap ring, which holds the mounting assembly on the sink flange. You’ll need to use a flathead screwdriver to remove the snap ring. Next, remove the mounting ring by inserting the screwdriver into the tabs and turning the mounting ring assembly until it is free from the tabs. Be sure to support the bottom of the disposer as you do this. After this comes off, the entire mounting assembly will come free from the sink flange. Once free, pull the sink flange out from the top of the sink and scrape or wipe any old putty off the sink before wiping it clean with a towel.
Now you’re ready to install the new disposer, which basically is the reverse of what we just did. You’ll start by applying a half-inch or three-quarter inch thick “rope” of plumbers putty around the sink flange.
Next, press the sink flange into the sink drain. The plumbers putty will squeeze out around the edges of the flange and should be removed with your fingers. To keep the flange seated properly in the sink drain, place a heavy object on a towel over the flange, such as the disposer.
The mounting bracket for your new garbage disposer assembles by inserting the fiber gasket, back-up flange and mounting ring over the sink flange, in that order. Be sure to hold these three pieces in place while you insert the snap ring over the flange. It’s called a snap ring because you’ll hear it snap in place. Then firmly tighten the three mounting screws against the backup flange, being careful to tighten them evenly.
If you are hooking your dishwasher up to drain through your garbage disposer, you’ll need to knock out the drain plug with a hammer and your flathead screwdriver and remove the plastic plug from inside the disposer with a pair of needle nose pliers. If you’re not hooking your dishwasher up, you’ll skip this step.
Next, you’ll connect the wires that you disconnected from the old disposer, to the new disposer. If this isn’t a replacement project, and you’re adding a new disposer where you didn’t have one before, you’ll first need to call an electrician to run the proper wires and a wall switch to the unit. For our project, the electrical wires and switch were already in place.
Your electrical supply wires should include a black (or hot) wire, a white (or neutral) wire and either a green or a bare wire, which is the ground wire. First remove the electrical cover plate on the bottom of the new disposer. Then move the new disposer into the cabinet. Screw the threaded end of the cable connector into the round hole on the bottom of the disposer. You’ll run your electrical supply wires through the cable connector and up through the access hole.
If not enough wire is exposed, you may need to strip some more of the wire’s insulation off the ends using a wire stripper. Connect the black wires to each other, then the white wires to each other, twisting the ends together in a clockwise direction with a pair of pliers. After twisting the ends together, cover the twisted wire with a wire nut, twisting clockwise until it is snug. Remember, “Righty Tighty, Lefty loosey.”
Next, connect the ground wire to the green grounding screw, making sure to hook the screw so the wire won’t loosen when you tighten the screw. Carefully push the wires back into the disposer and screw the electrical cover plate back on. Then tighten the screws on the cable connector to hold the supply wires firmly in place.
You’ll need to measure the new discharge tube to make sure it fits into the existing drain assembly. In our installation, the garbage disposer doesn’t use the discharge tube, but connects directly to the drain. If this isn’t a replacement project, you’ll need to tie in a drain assembly to the existing sink drain, which might take reconfiguring the drain. Be sure to reach the manufacturer’s instructions, and check out our Frequently Asked Questions section on this site for more information on how to do this, or visit your local independent home improvement retailer for the products and advice you’ll need for this step of the project.
The next step is to hang the new disposer by aligning the three mounting tabs with the slid-up ramps on the mounting ring assembly. Then turn the mounting ring until the three mounting tabs lock over the ridges on the slide-up ramps.
Rotate the disposer to align the disposer with the drain or the discharge tube, slide the flange over drain pipe or discharge tube and insert the gasket into the discharge outlet. Then screw in the bolts that secure the flange to the disposer. Reconnect all the plumbing connections as well as the dishwasher inlet hose. Then turn the power back on at the electrical supply panel and test the unit for leaks, making sure to run cold water while the unit is running.
There you have it. If you have questions about this or any other home improvement project, be sure to read our list of Frequently Asked Questions for this video. And be sure to print out our Project Instructions, which includes a Tools and Materials checklist, before visiting your local independent home improvement retailer. That’s where you’ll find all the products and helpful advice to complete your project. If you’re not sure where to find your local store, check out our Store Locator.
Good luck with your project and thanks for watching.
Turn off the power running to the garbage disposer.
Turn off the hot and cold water shut-off valves. These are usually located in the cabinet directly under the sink.
Disconnect the drain trap from the disposer's discharge tube.
Disconnect the slip fittings to the drain.
Disconnect the dishwasher inlet hose (if one is attached).
Hold the bottom of the disposer so it doesn't fall as you unscrew it from the sink. Turn clockwise.
Turn the disposer upside down and unscrew the electrical cover plate from the bottom.
Disconnect the electrical cable connector.
Pull out the wire nuts.
Unscrew the wire from the green ground screw.
Remove the mounting assembly if you're replacing with a new one.
If you're setting up the dishwasher to drain through the disposer, knock out the plastic drain plug and remove from the disposer.
Install the new disposer in the reverse order that you took the old one out. If you didn't have a disposer set up before, call an electrician to set up the wires first.