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No matter how good the quality, garbage disposal needs to be replaced after a few years. And there are two major reasons behind it. Either the waste disposal unit starts making a loud noise while it is on or the blades are not sharp enough to grind down food or leftovers properly. And no one likes to work around a kitchen sink from where horrific noises are coming. And also, dull blades mean frequent clogging of the sink. If you notice any of these two major signs, you know it’s time to install a new garbage disposal.

Installing in-sink waste disposal is no big deal. Anyone can easily fix the disposer under the sink with proper step-by-step instructions by side. Besides, the instruction manual is common with every new garbage disposal bought. In addition to the manual, many brands also provide basic tools for proper DIY garbage disposal installation. Make sure to read the manual thoroughly before you begin installation as it will only help you to finish the project on time.

The motor of waste disposal units ranges between 3/4 HP to 2 HP for residential use. While the horsepower may be different, some common installation steps help with DIY. And today we’ll be discussing those steps to help you with garbage disposal installation for the first time or replacement.

How to install a garbage disposal Guide

How To Install A Garbage Disposal Unit?

DIY installation is way more inexpensive than calling a plumber or professional. Plus, you’ll not need expensive stuff for such a simple thing. While important tools come with the disposer unit, you’ll need to take out a few household tools from the garage. Take a look at things you need to gather before installation.

Materials you’ll need:

  • Garbage disposer
  • Plumber’s putty
  • Wire nuts
  • Wiring kit(if not provided with disposer)

Tools you’ll require:

  • Compatible screwdriver
  • Putty knife
  • Pliers
  • Towels
  • Safety glasses
  • A small bucket
  • Hacksaw/PVC cutter

Step 1: The Basic Preparation

Whether installing garbage disposal for the first time or replacing the old one, always turn off the circuit. After removing the plug or turning the switch off, now its time to remove the existing assembly. Position the small bucket underneath the drain pipe. This will catch excess water while you unfasten the drain pipe.

After removing the P-trap drainpipe, push the sink strainer up to remove it too. Now grab the putty knife to scrape off the excess putty on the strainer edge. You can use towels to clean the spills or wipe clean the strainer edge after removing the putty.

Step 2: Preparing the New Waste Disposal

Take out the garbage disposal from the box and set the components nearby you while for easy access during installation. If the flange is already pre-assembled, then well and good as you’ll not have to go through the confusing part. But not to worry if you have to assemble the parts by yourself. First, collect the components that go underneath the sink. This usually has a ring, fiber gasket, mounting ring, and a backup flange.

Take the new drain strainer and apply the plumber’s putty around the flange. Do not hesitate to use a little more putty and you can scrape the excess off once the drain sits in the hole perfectly. Lay a towel on the top of the new drain and put a heavy object over the towel. This will fix the new drain properly in place. You can put the garbage disposal unit itself if you find no heavy object nearby.

By the time putty dries, stack the fiber gasket or rubber whichever comes along with your new garbage grinder. After the gasket, goes in the backup flange and mounting ring on the underside of the flange. And finally goes the snap ring. Pull it open a bit and snap it into place. Fasten the screws of the place using a screwdriver. But make sure not to overtighten them. Just apply enough pressure to keep everything in place.

Step 3: And the Installation Begins

Take your new waste disposal unit and attach the tailpipe to the rubber seal on the side. Secure the ring with a metal ring. You’ll not need a metal ring in case your unit comes with a metal bracket. In this case, directly connect the tailpipe to the rubber seal and tighten it properly.

Now it’s time to do some work with power cords. Many disposal units do not have an attached power cord. And if your unit does not have one then it will have a small electric cover plate on the bottom of the garbage disposal. Remove the electric plate with the help of a screwdriver. This will give you access to the disposer’s electric wiring.

You’ll see different color wires on the removal of the plate. Now the task is very simple, you need to connect the matching-wires using wire nuts. The white wire of the disposal connects to the white wire of the power cord, the black connects with the black cord and the green one goes with green ground wire. Tuck the wires properly before pushing them back down and reattaching the plate.

Step 4: Mounting New Garbage Disposal

Disposers are quite heavy to lift and mount up in the place. Be careful not to strain your arms while mounting. You can ask for help if you find your new unit too heavy. Begin by aligning the rubber ring of the garbage grinder on the top with the flange underneath the sink. This might take a bit of time if you’re installing a waste disposal unit for the first time.

Once the unit hangs properly aligned with the three tabs of the mounting ring, lock the tabs in place. Use the included wrench to turn and lock the tabs over the ridges.

Step 5: Final Connections

Once your new garbage disposal unit is properly hung under the sink, it’s time to connect the disposer to P-trap. Use the hacksaw/PVC cutter to trim the long P-trap pipe. Use a T-pipe before connecting P-trap to the disposer. Once the drain connection is complete, check for all the connections one more time.

Insert the drain stopper and fill the sink with water. Let the water sit for a while to check the leaks. Fix the leaks, if any, either by applying the plumber’s putty or by fastening the connections. If everything is perfect, plug in the garbage disposal and turn the machine on. You can now start pushing the leftovers and kitchen waste down the drain. Happy griding until it’s time to replace the old in-sink disposal.

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How to Install Garbage Disposal with Dishwasher?

If you wish to connect your dishwasher with garbage disposal then simply knock off the breakout present in the disposal with the help of a hammer and a screwdriver. Here goes the dishwasher line. Secure the dishwasher hose with the clamp provided when you attach the unit with the P-trap pipe.

(Note: Do not break the breakout-plate if you’re not going to connect waste disposal with an automatic dishwasher)


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