Hi, this is Jerica from InSinkErator Customer Service. Yes, there is a knockout plug that has to be removed if you are going to connect your disposer to a dishwasher. Kindly follow the steps below on how to properly remove the disposer’s knockout plug.
1. Disconnect electrical power at the fuse box or circuit breaker box.
2. Remove the disposer from the sink per the instructions in your Installation Care and Use Manual.
3. Position the disposer on its side, on a protected floor or workbench, with the dishwasher inlet tube facing up.
4. Using a flat-head screwdriver, insert it into the dishwasher inlet tube so as to set the tip on the molded outer edge of the plug located at the end of the tube.
5. Take a hammer and tap the screwdriver all the way around this edge until the plastic plug breaks loose and falls into the disposer grind chamber.
6. Be sure to retrieve the plastic knockout plug from inside the grind chamber. Making sure power is still OFF to the disposer, turn it upside down and shake it out or, as a second option, shine a flashlight into the chamber, locate the plastic knockout plug, and use a long tongs or pliers through the top opening to pinch it and pull it out. Do NOT place your hands inside the disposer.
7. Reinstall the disposer per the instructions in your Installation Care and Use Manual.
I have also included below the link of the disposer’s Installation Care and Use Manual. You may refer to steps 15 and 16 for the visuals of removing your disposer’s knockout plug.
http://www.insinkerator.com/en-us/D....
If you have questions, you may contact us through insinkeratorfeedback@emerson.com or call InSinkErator AnswerLine at 1 (800) 558-5700. Thank you.