Installations - Garbage Disposals

First patented in 1927, by 1948 General Electric was mass producing and marketing electric garbage disposals. Since that time they have remained a popular kitchen accessory; adding convenience to mealtime preparation and cleanup tasks in households in those localities that do allow them.

Disposals help reduce urban and landfill waste. And the amount of garbage collected and disposed of by city services. However, they also increase the maintenance costs of municipal wastewater treatment plants, which is why some localities ban their use.

Before installing a garbage disposal in your kitchen, check local building codes to make sure they are allowed in your area. Also check what type requirements may be in place for their set up. For instance, most codes specify that the disposal must be plugged into a grounded unit, and that they are controlled by an on and off switch.

Types of Disposals

Garbage disposals are one of two types; either batch-fed or continuous feed. A batch-fed disposal runs only when the drain lid is in place; they are operated by turning a special stopper after the disposal receptacle has been loaded with food debris. Because this type disposal can only be activated while the cavity is covered by the inserted stopper, these type disposals represent a safer choice.

Continuous feed models are activated by a switch that allows you to add waste while the motor is turned on. Running water helps to flush food scraps down the disposal as they are added. The motor continues to run until the switch is turned off. Both types of disposals attach to the sink drain system.

The switch should be located on the wall to back of the sink, as far from the edge of the counter as possible; or in an out of the way place for safety purposes. Switch location is an important consideration; especially in households with small children.

The Installation process

A new dedicated 20 amp circuit should be installed under the sink in close proximity to power the new garbage disposal. Although switches and outlets should be installed by an electrician, installing the garbage disposal itself isn’t all that difficult for the resourceful homeowner with some plumbing knowledge.

Installation is relatively uncomplicated. Requiring the use of silicone caulk or plumber’s putty, mineral spirits, and only the most basic of tools to accomplish the task; both flat-tip and Phillips-head screwdrivers, a utility knife, hose clamps, pipe wrench, slip nuts, beveled washers, and a flashlight.

Before installation, make sure that the dedicated circuit for the disposal is turned off at the circuit box. Do this by either turning off the breaker or removing the fuse.

Now you are ready to begin the installation process; follow these simple steps:

• Remove the existing drainpipe and p-trap using the pipe wrench; place a bucket or another container underneath to catch any water remaining in the drainpipe.
• Remove the strainer body from the sink by unscrewing the large nut that holds it in place under the sink. Be sure to scrape off any old putty from around the sink opening, and then clean the opening completely using denatured alcohol or mineral spirits.
• Apply a bead of silicone caulk or plumber’s putty under the edge of the drain opening sleeve. Insert the sleeve into the drain opening; press down evenly to ensure a good seal.
• Working underneath the sink, place the fiber gasket and backup ring onto the sleeve. Attach the lower mounting ring onto the sleeve and put the snap ring in place.
• Position the disposer against the lower mounting ring; line the lugs up with the mounting screws, and then tighten the screws. Be sure and alternate tightening each screw so the mounting bracket is evenly seated against the bottom of the sink.
• Remove the bottom plate on the disposer to expose the wiring. Position the garbage disposal under the sink; connect wires from the garbage disposal to the wires from the power source with wire nuts; white to white, and black to black.
• Connect the green ground wire from the disposal to the green ground wire on the power source; replace the disposer’s bottom plate to cover the wires.
• Fasten the discharge tube to the discharge opening with the mounting washer.
• If a dishwasher will be attached to the disposal, remove the knockout plug from the dishwasher opening. Carefully tap it out using a screw driver and hammer; attach the dishwasher drain hose with a hose clamp.
• Attach the drainpipe to the discharge tube and gasket using a slip nut and beveled washer. If the discharge tube is too long, cut it to fit. If it is too short, purchase an extension piece. Make sure the washer faces the threaded drainpipe.
• Secure the disposal by inserting a screwdriver into the mounting lug located on the lower mounting ring. Tighten the mounting lug screw.

Once installation is complete, test the unit out and check for any leaks.

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