Garbage Disposal Installation Guide
Garbage disposals are efficient, safe and virtually trouble-free devices that anyone who knows how to use a screwdriver and wrench can install in a few hours. Batch-feed models, touted for their safety, are similar to a food processor. Once it is filled with waste, it’s activated when the sink plug is twisted into the sink opening. Whereas, a continuous-feed disposal is operated by a switch on the wall or cabinet, and runs continuously while waste is fed into the grinding chamber.
Cold water must be kept running while a disposal is in operation. The water cools and lubricates the grinding parts and helps to send the pulverized waste down the drain.
Step 1. Remove Drain
Remove the existing waste (drain) pipes from the sink strainer to the threaded fitting at the wall or floor (stubout). If the removed piping is plastic with compression (threaded-type) fittings, you can possibly reuse it. But if the pipe is welded or metal, throw it away. Unscrew the fittings by hand or with groove-joint pliers and use a hacksaw to cut the welded pipe.
Tip: Catch Standing Water
Place a plastic dishpan under the drain trap to catch standing water as you either remove the drain plug, if there is one, or disconnect the trap.
Step 2. Replace Sink Strainer
Remove the sink strainer fitting that is secured to the sink bowl. One type of strainer is held with a large lock nut, but there are types that use three screws. In its place, install the flange that comes with the disposer. Apply plumber’s putty under its lip to form a seal with the sink bowl.
Step 3. Install Mounting Assembly
Slip the mounting assembly gasket and mounting and retaining rings over the neck of the sink flange and tighten the screws. First tighten one, then the others a little at a time until the gasket and flange are both tight to the sink bowl. Remove excess putty from around the flange inside the sink.
Step 4. Mount Disposal
Before you mount the disposal, make the wiring connections at the disposal. Be sure to allot enough cable to extend to the power source (see Step 6). Reattach the drain elbow. If you have a dishwasher, prepare the disposal drain following the manufacturer’s instructions. Slip the disposal’s slotted flange over the mounting bolts.
Step 5. Connect Plastic Waste Pipe
Connect a two-piece tubular P-trap to the drain elbow and the drain fitting at the wall (stubout). As needed, cut the P-trap and rotate both the trap section of the P-trap and the disposal. Complete tightening the waste pipe fittings and the disposal. Connect any dishwasher hose to the disposal’s drain fitting with a stainless steel hose clamp.
Step 6. Power Connection
If you have electrical wiring experience and plan to make the power connection to the disposal, be sure to first turn off the power before beginning the work.
Disposals need to connect to a grounded 20-amp circuit. The steps in order to connect power differ with each type of disposal. For example, continuous-feed disposals are wired to an on/off switch located on a wall or in the sink cabinet. Whereas a batch-feed disposal has its own integral switch and is hard-wired or plugged directly to the wall outlet. It is best to have an electrician handle this part of the job if you are not knowledgeable about local code requirements and basic electrical wiring.
Tip: Air Vents and Disposal Jams
Once in a while you will find that the air vent on the sink will overflow when the dishwasher is running. This is because the disposal has thrown waste into the dishwasher drain hose and has partially clogged it. When this happens, remove the hose from the disposal, clean it out with a hanger and replace the hose.
If the disposal ever jams, quickly turn it off. Use the end of a wooden mop wedged against the opening of the disposal to loosen the blades that are located at the bottom of the disposal. In some instances, the reset button (usually located at the bottom of the disposal) will have to be pushed in order to return power.
Never discard rice, nut shells, pits, or fibrous waste into the disposal. And, for continuous-feed disposals, never force large volumes of anything at one time since it could cause a drain clog.
