Document ID: SOP-PLM-004
Applies To: All standard InSinkErator® continuous and batch-feed food waste disposers
Skill Level: Apprentice / DIY
Estimated Time: 5–10 Minutes
Overview & Operational Context
An InSinkErator® disposer relies on an internal thermal overload switch designed to trip whenever the motor encounters excessive electrical resistance, mechanical jamming, or overheating. When tripped, the switch cuts power to protect the motor windings from burning out. Resetting the unit restores normal circuit continuity once the underlying fault or obstruction has been cleared.
Tools & Equipment Required
- Safety Goggles
- Flashlight or Headlamp
- InSinkErator Jam-Buster® Wrench (or standard 1/4-inch hex/Allen key)
- Pliers or Tongs (optional — for removing internal obstructions)
1.Disconnect Electrical Supply:Safety Prerequisite — Mandatory Before Hands-On Service.
Prior to touching the unit, isolate it from all electrical power sources:
- Plug-in units: Disconnect the electrical cord directly from the wall outlet beneath the sink cabinet.
- Hardwired units: Locate your home’s main electrical panel and switch off the dedicated circuit breaker supplying power to the kitchen disposal. Verify power is completely cut before proceeding.
2.Locate the Red Overload Reset Switch:Physical Inspection.
Position yourself beneath the sink and inspect the underside of the disposal housing:
- Direct your light toward the bottom exterior plate of the unit.
- Locate the red, rectangular push-button set into the lower casing (typically positioned near the center or bottom-side edge).
- Diagnostic check: If the button is extended outward by roughly $1/4$ inch, the thermal relay has tripped.
3.Inspect & Clear Internal Impeller Plate:Clear Mechanical Blockages First.
Do not force the reset button if the grinding chamber is jammed.
- Shine a light directly down through the sink drain to check for trapped objects (e.g., bones, utensils, fibrous scraps).
- Insert a 1/4-inch hex key into the socket located in the center of the bottom baseplate underneath the unit.
- Work the key back and forth clockwise and counterclockwise until the internal shredder plate rotates freely through a full $360^\circ$ sweep.
- Use tongs or pliers through the top sink opening to extract any loosened debris.
4.Depress the Reset Button:Engage Thermal Relay.
- Once the grinding chamber rotates smoothly without friction, press the red reset button firmly inward until you feel a distinct click.
- Hold the button in for 10 to 15 seconds to ensure the bi-metallic strip latches into place.
- Note: If the button snaps back out immediately, allow the motor body to cool down for 10–15 minutes before attempting again.
5.Restore Power & Test Functionality:System Verification.
- Reconnect the unit to the wall outlet or flip the circuit breaker back to the ON position.
- Turn on the cold water tap to a steady flow.
- Flip the wall switch to energize the disposer. The unit should immediately spin smoothly without hums, grinding chatter, or motor strain.
Troubleshooting Matrix
| Symptom | Probable Cause | Corrective Action |
| Silent when switched ON; reset button trips again immediately | Motor thermal overload hasn’t cooled down OR internal short circuit | Allow unit to cool for 20 mins. If issue persists, test outlet voltage or replace unit. |
| Humming sound, but plate does not rotate | Jammed flywheel / foreign object | Disconnect power. Use 1/4″ Allen wrench on base socket to manually break jam. |
| Button clicks and stays in, but unit shows no power | Tripped breaker at electrical panel or loose wiring connection | Check main switchboard breaker; inspect wire nut connections in junction box. |
Pro Tip: Always run cold water before, during, and 15 seconds after operating your disposer to solidify grease and assist waste passage through the branch line.