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Install New Disposal — Install Garbage Disposal and Prepare Dishwasher Connection

Beginner

Part of project

How to Plumb a Double Kitchen Sink Drain with a Garbage Disposal · Step 2 of 8

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In this video

If your disposer connects to your dishwasher, remove the knockout plug from the disposal by tapping with a hammer and screwdriver. Remove the plug from the disposer (it can be ground up if left in, or left in place if you don't have a dishwasher). If the disposal is hardwired, remove the electrical access plate and attach the wires according to the instructions. Lift the unit up to the mounting flange, align it, and twist the locking ring with a screwdriver until it locks into place. Reattach the drain lines to the disposer. If the disposal is larger than the old one, cut down the drain pipe with a hacksaw. Clean excess putty from the sink flange. Put a bucket or pan under the disposal, turn the water back on, and check for leaks. Plug in the disposal or turn the power back on and test again. Consult the owner's manual for items that can and cannot be put down the disposal.

Goal: Garbage Disposal Installation

  • Always double-check all connections before restoring power and water.

Used in this video

  • Hammer · optionalRemoving knockout plug
  • ScrewdriverRemoving knockout plug and locking ring
  • Hacksaw · optionalCutting drain pipe
  • BucketCatching leaks
  • Pliers · optionalConnecting drain lines
12.2K views7215 minutes
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FAQs

How difficult is it to plumb a double kitchen sink with a garbage disposal for a beginner, and how long should I expect it to take?

This project is rated as beginner-friendly, but requires patience and attention to detail. For a DIY novice, plan to set aside 3-5 hours, especially if you encounter unexpected issues or need to make precise cuts. The material cost, including the disposal and plumbing parts, typically ranges from $150-$400 depending on the quality and features chosen.

Are all the listed tools, especially specialized cutters and reamers, truly essential for this plumbing project?

While basic tools like Channellock pliers and a screwdriver are essential, specialized tools like the RIDGID PTEC 3000 plastic tubing cutter and the Husky Reamer are highly recommended. They ensure clean, burr-free cuts on plastic pipes, which significantly reduces the risk of leaks and makes assembly much easier. You could use a hacksaw for cuts, but meticulous deburring would then be critical.

What are the most common mistakes that lead to leaks after installing a double sink drain and garbage disposal, and how can I prevent them?

The most common causes of leaks are improperly tightened slip-nut connections, not using plumber's putty correctly around the sink flange, and misaligned P-trap components. Always hand-tighten slip nuts first, then use your Channellock pliers for an additional half-turn, ensuring all washers are seated perfectly. Thoroughly test for leaks by running water and inspecting every connection with paper towels.

What specific safety precautions should I take when working under the sink, especially with a garbage disposal and water lines?

Safety is paramount. Always disconnect power to the garbage disposal at the circuit breaker before beginning any work on it. Turn off the water supply to the sink at the shut-off valves or main house valve. Wear safety glasses to protect your eyes from debris, and use gloves to avoid contact with old grime or chemicals.

Transcript
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overtighten step four installing the new disposal if your new disposer will connect to your dishwasher remove The Knockout plug by tapping with a hammer and screwdriver then remove the plug from the disposer if you cannot get it out you can leave it in there and the disposer will grind it up within a few days if you do not have a dishwasher leave the plug in place if your new disposal is hardwired remove the electrical access plate and attach the wires according to the manufacturer's instructions lift the unit up to the mounting flange align it and using a screwdriver twist the locking ring until it locks into place now you can reattach the drain lines to the disposer if you're installing a disposer that's locked larger than the old one you may have to cut down the drain pipe to fit with a hacksaw clean any excess Putty from the sink flange put your bucket or pan under the disposal and turn the water back on check underneath for any leaks if everything is fine plug the disposal in or turn the power back on and test it again check your owner's manual to see what you can or cannot put down your garbage disposal to stay up to

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