Chapter 1 — What You’re Actually Solving

A garbage disposal has three failure modes. Two of them are replacement; one isn’t.

You’ve got a kitchen sink disposal that’s doing one of these:

• Hums but doesn’t grind. Something jammed the impellers. Not necessarily a replacement. See “Don’t replace yet” below.
• Makes no sound at all when flipped on. Motor or switch dead. Usually replacement.
• Grinds but leaks from the bottom or the sides. Seal failure. Replacement.
• Makes awful grinding/scraping sounds. Bearing failure. Replacement.
• Old and you just want a quieter/more-powerful model. Replacement by choice.

This book is about replacement. Before you commit, let’s rule out the cases where it’s not.

Don’t replace yet — check these first

Hum but no grind: 1. Flip the switch off. 2. Under the sink, the disposal has a red RESET button on its bottom. Press it. 3. On the bottom of the disposal you’ll find a hexagonal hole (1/4-inch socket or the disposal’s included Allen key). Insert the Allen key, turn back and forth to free the impellers. 4. Remove whatever’s jammed (usually a piece of silverware or a chunk of food) from the drain opening with pliers — NOT your hand. 5. Flip the switch on. If it grinds normally, you’re done. $0.

No power at all: 1. Check the switch on the wall. On? 2. Check the breaker. Tripped? 3. Is the disposal plugged in? (Most are — check the outlet under the sink.) 4. If all those are fine, press the RESET button on the disposal. 5. Still nothing? Motor is dead. Replacement.

If you’ve ruled those out and confirmed replacement is the answer, keep reading.

What this book covers

• Assessing what you have and what fits (HP, mounting, dimensions).
• Buying a replacement.
• Disconnecting the old unit (electrical, plumbing, mount).
• Installing the new mount assembly.
• Hanging the new unit.
• Wiring 120V with one switch.
• Plumbing — drain tailpiece and dishwasher connection.
• Testing for operation and leaks.

What this book doesn’t cover

• Hardwired disposal conversion to plug-in (or vice versa). Not hard but scope creep.
• Installing a switch from scratch. Covered in Replace a Kitchen Switch.
• Under-sink water filter interactions. If you have a filter that shares plumbing with the disposal, consult your filter manual for disconnect/reconnect.

What you’ll be able to do by the end

Replace a standard 1/2-1 HP continuous-feed garbage disposal in about 90 minutes the first time. Second time, 45. Connect a dishwasher to it (or bypass), wire it to an existing switch, and leak-test the installation.