A garbage disposal makes life in the kitchen much easier, but like any appliance, it can wear out and need replacing. Here’s a guide to help you replace your old disposal with a new one:
Safety First!
- Turn off the power to the garbage disposal at the circuit breaker box. Locate the breaker labeled “kitchen” or “garbage disposal” and switch it to the “Off” position.
- Close the shut-off valve under your sink to stop the water supply.
Tools You’ll Need:
- Adjustable wrench
- Phillips head screwdriver
- Flathead screwdriver
- Bucket
- Plumber’s putty
- New garbage disposal (ensure compatibility with your sink)
- Optional: Work gloves, flashlight
Removing the Old Disposal:
- Empty the disposal: Use the disposal wrench (usually included with the new unit) to turn the disposal manually and remove any debris.
- Place a bucket under the disposal: This will catch any water or debris that spills out during removal.
- Disconnect the dishwasher drain (if applicable): Locate the dishwasher drain hose connected to the disposal inlet. There might be a clamp holding it in place. Loosen the clamp and carefully detach the hose.
- Disconnect the drainpipe: The disposal discharge pipe connects to the P-trap (the curved pipe under the sink). Loosen the slip nut or clamp that secures the connection.
- Disconnect the power cord: There’s usually an access plate near the bottom of the disposal. Open it and carefully detach the wires from the disposal’s terminal block (refer to the new disposal’s manual for proper wiring if needed).
- Remove the mounting ring: Most disposals secure to the sink flange with a mounting ring. Use an adjustable wrench to loosen the mounting ring nuts and detach the disposal from the sink flange.
- Tip: The disposal can be heavy. Have someone support it from below as you loosen the mounting ring.
Installing the New Disposal:
- Prepare the sink flange: If replacing the flange, apply a ring of plumber’s putty around the underside of the new flange. Press the flange firmly into the sink drain opening.
- Install the mounting ring: Slide the mounting ring, backup flange (if included), and gasket (if included) onto the new disposal, following the manufacturer’s instructions.
- Mount the disposal: Carefully lift the disposal with the mounting ring assembly into place and secure it to the sink flange by tightening the mounting ring nuts.
- Connect the drainpipe: Attach the disposal’s discharge pipe to the P-trap using a slip nut or clamp and tighten securely.
- Reconnect the dishwasher drain (if applicable): Reattach the dishwasher drain hose to the disposal inlet and secure the connection with a clamp.
- Electrical connection: Following the new disposal’s manual, connect the wires from the power cord to the corresponding terminals on the disposal’s terminal block.
- Caution: Ensure all wire connections are secure and no bare wires are exposed. Double-check the wiring diagram before turning on the power.
- Test the disposal: Turn on the water supply and the circuit breaker for the disposal. Press the disposal reset button (usually located on the bottom) and run water into the sink. Turn on the disposal and test it with a small amount of soft food scraps.
Additional Tips:
- If your new disposal has a knockout plug for the dishwasher connection, and you don’t use it, make sure to plug it securely to prevent leaks.
- Check for leaks at all connection points after running the disposal for a few minutes.
- Refer to the new disposal’s manual for specific installation instructions and troubleshooting tips.
By following these steps, you should be able to successfully replace your old garbage disposal with a new one. If you’re not comfortable with DIY projects, it’s always best to consult a licensed plumber for assistance.
Chapman’s Plumbing, Heating, and Air offers plumbing services, including garbage disposal maintenance and replacement, in the Alleghany Highlands. We’d love to solve your problem!










