Plumbing Tips: Install Garbage Disposal
The first thing you should do is to see how the unit is wired. If it has a cord with a plug, then simply unplug it from the receptacle. If it is hard wired, find the breaker or switch and turn it off.
STEP 1: Disconnect the 1½" drain tube that connects to the disposal and set aside. In some areas the dishwasher drain line may drain into the disposal at the neck. Remove this line and tie up out of the way. Turn the locking ring that holds the disposal to the flange assembly; it usually can be done with a screwdriver. This will enable you to set the disposal down on the cabinet base.
STEP 2: At the bottom of the disposal, remove the electrical cover plate. Being sure the power is off! Remove the wire nuts and disconnect the ground wire. Pull the wiring out of the disposal. You may want to remove the wire connector that holds the wire into the disposal and use it on the new one.
STEP 3: The new 1/2 and 3/4 HP Insinkerator disposals. Remove the flange assembly from the top of the disposal by turning the aluminum lock ring clockwise.
STEP 4: Lay out the flange assembly roll out a ½" diameter rope of plumber’s putty. Put it around the underside of the chrome flange. Coat the rubber gasket with pipe dope on the side that will join the sink.
STEP 5: Place the flange piece through the hole in the sink. On the underside of the flange, slip the rubber gasket, then the paper gasket—in that order—over the threads. Screw the plastic nut on the flange piece, and tighten with a wrench (DO NOT OVER TIGHTEN). Next, slip on the aluminum lock ring. Last, slip on the rubber flange piece that will join to the disposal. Clean any excess putty from the flange in the sink.
STEP 6: Remove the electrical plate from the bottom of the disposal. Install the wire connector in the hole provided. Pull the two wires out of the disposal and strip the black and white wire about ½" from the end of each wire. Place the existing power wire into the connector and pull it into the disposal. Hook the copper ground to the green screw, connect the wires, black to black and white to white with wire nuts. Replace the cover plate.
STEP 7: If the existing drain from the dishwasher drained into the disposal, and you want to do the same, then you must remove the plastic plug that is molded into the nipple as shown. Knock out the plug using a screwdriver and hammer. Leave the plug in if you are not going to use this drain.
STEP 8: Assemble the black elbow drain fitting to the side of the disposal. You may want to put some pipe dope on the rubber gasket. Tighten the two screws through the metal flange.
STEP 9: With one hand, raise the disposal up to the flange assembly. Line up the locking ring with the studs on the disposal. With the other hand turn the locking ring counterclockwise until the ring locks. Place the dishwasher drain hose onto the connection at the top of the neck and tighten the hose clamps. If possible, turn the disposal so that the drain is in the back and the Mr. Rooter nameplate is showing on the front.
STEP 10: If you are lucky, the old piping will line up with the new disposal. If not you may have to cut or turn the black drain elbow. Using a new continuous waste pipe or the existing pipe, reassemble the drain.
STEP 11: Always use NEW rubber or nylon gaskets. Always use pipe dope on the gaskets.
STEP 12: Turn the water on to the sink and test the disposal and drain for leaks. Turn the electrical power on while the water is running. Check for operation as described in the installers’ manual.
Congratulations! You have successfully completed the job!