Replace or Install a Garbage Disposer

Step 1

As always, while working with electricity, turn off the electrical supply at the breaker panel in your home! Then test that you indeed have the supply turned it off by using a volt/multimeter where your working, prior to starting your project.

Step 2

REMOVE THE OLD DISPOSER
Disconnect the drain lines; there are typically two lines, one is the main drain coming from the disposer, through a p-trap and then in the main waste line for the whole sink, and is usually connected to the disposer with a metal flange. The second hose is a discharge into the disposer that comes from a dishwasher, if installed. This hose is normally flexable, and is normally secured with a typical hose clamp. When removing these lines be ready for the possible spill, and make sure any water is cleaned up prior to proceding to the next step.

Step 3

Remove the cover on the underside of old disposer to reveal wiring. Disconnect the ground wire leading to the disposal, and remove the wire nuts to disconnect power and neutral wires. Again, make sure the power is disconnected first!

Step 4

Disposers are mounted in various ways, but the one shown is the most common. To remove this disposer, use the tool that came with the disposer (looks like an Allen wrench) or a screwdriver to pry on the lower ring rotating it counter-clockwise. It should only take about a quarter turn to remove, and the disposer should just fall away. Make sure you support the disposer, because it is fairly heavy, considering working under a sink.

Step 5

Next, loosen the three corner screws to remove the drain assembly. Once the screws are loose you can remove the second and third rings by removing the retaining ring on the bottom of the assembly. Finish the assembly removal by pushing the drain up through the sink. After the old drain is removed, clean the surrounding surface of old plumbers putty, caulk, or residue.

Step 6

Roll and place a 3/8"-1/2" thick and 10" long bead of plumber's putty on the opening of the drain or on the new drain flange.

Step 7

Press the new drain in place, so the writing on the flange is readable as viewed from the front of the sink. Remove any eccess plumber's putty with a scraper or screwdriver.

Step 8

Install the remainder of the drain assembly. If your installing a similar garbage disposer, install reverse installation. In this case, a cardboard washer is installed on the drain spud, followed by the backup ring, mounting flange, and retaining ring. Tighten the three flange screws, as shown. Alternate between screws, this ensures an even and tight fit of the backup ring against the drain. After tighening the screws, go back and scrape off excess putty as in Step 7.

Step 9

It's ussually best if you wire the disposer up prior to securing to the sink drain. To do this first thread a electrical box connector in the base of the disposer, as shown. Once secure, fish the wiring through this box connector and back out the wiring access panel. Secure the wire at the box connector. Many installations use an industrial power cord that plugs into a GFC outlet under the sink, instead of flexable conduit. If this is the case, still use a electrical box connector, because it's designed to prevent cutting through the wire insulation.

Step 10

After the wires are secure, join the black wires together in one wire connector, the white wires togehter in another wire connector, and secure the ground wire to the green screw inside the disposer access panel. Carefully stow all connected wires into the access panel and replace the cover.

Step 11

After wiring is complete, knock out the dishwasher discharge plug. New disposers come with a dishwasher discharge drain, which comes plugged. If your dishwasher drains into the disposer, like this installation, you need to remove this plug by knocking it out with a screwdriver and removing it from inside the disposer. Once this is accomplished, lift up the disposer to the drain flange and rotate clockwise to hand tighten.

Step 12

Further tighten the disposer clockwise with the provided Allen wrench or a screwdriver.

Step 13

Reconnect the drain line from your dishwasher (if installed) and tighten its hose clamp, then reconnect the disposer drain with new or existing pumping. If your using a similar model disposer, the existing plumbing should work. Otherwise replumb the disposer so that the dishwasher drains into a P-trap under the sink. To secure the drain line to the disposer, place the metal flange ring over the PVC pipe, followed by the rubber gasket. Secure the metal flange ring to the disposer. Depending on the disposer, securing this ring is accomplished with two bolts, or one bolt and a tab that slips into a slot on the disposer body.

Step 14

After installation, run water through the drain with the new disposer and check for leaks. Additionally, the first time you run your dishwasher, you should check for leaks. If there are no leaks, you may turn on the power to the disposer and give it a test drive. Check for leaks again.

A side note...while the drain lines for the sink and dishwasher are disconnected, make sure to tell members of your household to not use those respective items! Otherwise it can get pretty wet!

: Tue May 23, 2006 3:05 pm

Very nice and informative article. A great addition to our collection!