Installing a New Disposal

If you've just purchased a new InSinkErator disposal, you'll be glad to know our disposals are the easiest to install.

Watch & Learn

InSinkErator shows you how to install a garbage disposal by following the steps outlined in the instructions manual and as shown in this 4-minute video.

Written Directions

Before attempting to install your disposal, read and understand the entire InSinkErator safety and installation instructions listed below.

Materials Needed

Plumber's Putty (.1 kg)
Wire Nuts (2-size 54)
Worm Gear Clamp
Dishwasher Drain Connector Kit (optional)
Channel-Lock Pliers
Flathead Screwdriver
Phillips Screwdriver
Pipe Wrench




Disconnect the p-trap and the horizontal extension pipe.

Large channel-lock pliers or a pipe wrench work well to loosen the nuts holding the pipes together. When both connections are free, remove the parts. You may want to clean the horizontal drain pipe to eliminate any possible blockage. (This is not necessary in new construction.)


Disconnect the down drainpipe.

Using large channel-lock pliers, disconnect the down drainpipe coming from the sink and the connection that attaches it to the p-trap. When both connections are free, remove the parts. (See Fig 1)


Unscrew the large nut.

Unscrew the large nut that holds the strainer in place underneath the sink. Remove the strainer body.


Pry off snap ring and clean off the old plumber's putty.

Using a flathead screwdriver, loosen the 3 screws on the mounting assembly and pry off the snap ring. Clean off the old plumber's putty that surrounds the edge of the drain opening.


Install the new sink flange.

Place a 1/2" rope of plumber's putty around the drain opening in the sink. Drop the new sink flange into the drain opening and press it into place. Placing a weight, such as your disposal, on top of the sink flange will help hold the sink flange in place while mounting it to the sink. To avoid scratching your sink or the flange, place a towel between the sink surface and the weight. (See Fig 2)


Install gasket and flanges.

From under the sink, slide the fiber gasket, backup flange and mounting flange over the sink flange. Hold these pieces in place.


Slip on the mounting and snap rings.

Next, slip on the mounting ring and snap ring. Tighten the three mounting screws, alternately tightening each screw a few turns at a time until the mounting assembly is evenly and tightly seated against the bottom of the sink.


Remove the dishwasher knockout plug.

If using a dishwasher, you will need to tap out the dishwasher knockout plug. Lay the disposal on its side and use a screwdriver and hammer to tap it out. Next, remove the loose knockout plug from inside the disposal. (See Fig 3)


Connect the electrical.

Lay the disposal on its side under the sink so you can make the electrical connections. Make sure the circuit breaker is off. Remove the plate on the bottom of the disposal to expose the wiring and use wire nuts to connect the wires from the disposal to the matching wires from the power supply. Finally, secure the power cord to the bottom of the disposal using the proper connection. Replace the plate to cover the wires. (See Fig 4)
If you're looking for power cord kit installation instructions, click here.


Hang the disposal.

Hang the disposal by aligning the three mounting tabs with the slide-up ramps on the mounting ring. Holding the disposal in place, turn the lower mounting ring until all three tabs are locked into the mounting assembly. (See Fig 5a)


Insert the discharge tube.

Insert the discharge tube into the discharge coupler, then slide the clamp over the discharge tube and position it in the groove on the rubber tailpipe coupler. (See Fig 5b)


Align the discharge tube with drain pipe.

Rotate the disposal so that the discharge tube is aligned with the drain trap. If the discharge tube is too long, cut off as much of the tube as necessary. If it is too short, you can purchase an extension. If you are connecting the disposal to a dishwasher, it may be connected through an air gap. Use a hose clamp to attach the drain hose to the dishwasher inlet. (See Fig 5c)


Lock the disposal in place.

Now that everything is installed and in position, lock the disposal to the sink mounting assembly using the special wrench that came with the unit. Insert the Quiet Collar® Sink Baffle into the sink opening by pressing it into the sink until it snaps into place. (See Fig 5d)


Test the disposal.

Test for leaks at the sink flange, dishwasher, tail-pipe and mounting assembly connections. Finally, turn on the electrical breaker to test its operation.

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