A sudden garbage disposal failure can disrupt the kitchen flow. Fortunately, many common problems can be resolved with simple troubleshooting. Before attempting any inspection or repair, always turn off the wall switch controlling the unit to prevent accidental activation. Understanding the specific symptom—whether it is silent, humming, or running poorly—will guide you to the correct solution.
The Silent Disposal: Power Issues
A disposal that makes no sound when the switch is flipped indicates a complete lack of electrical power reaching the motor. This is often the easiest problem to fix, as the unit is likely protecting itself from an overload. First, check the main wall switch to ensure it is in the “on” position, as an accidental flip can be the cause.
If the switch is on, locate the small red or black reset button on the bottom of the disposal unit. This button functions as a thermal overload protector. When the motor overheats or draws too much current, this internal circuit breaker trips, cutting power to prevent damage. Press the button firmly until you hear a click, which resets the breaker and restores the electrical connection.
If the reset button does not stay in or the unit remains silent, the issue may be further up the electrical line. Check the main circuit breaker panel to see if the breaker controlling the kitchen or disposal line has tripped. Flipping the breaker completely off and then back on can restore power. If the breaker trips repeatedly, it suggests a serious electrical fault or a failing motor.
The Humming Disposal: Clearing a Jam
A humming sound without grinding indicates the motor is receiving power but the flywheel is mechanically jammed. This usually happens when a hard object, such as a bone or metal, is caught between the impeller and the grinding ring. Before proceeding, turn off the wall switch and, if possible, unplug the unit from the outlet under the sink.
To clear the jam externally, locate the hexagonal hole in the center of the disposal’s underside, which is the motor shaft access point. Insert a 1/4-inch Allen wrench (or hex key) into this socket. Manually turn the motor shaft back and forth to apply leverage to the flywheel, helping to break the obstruction free. Continue rotating the wrench until the shaft spins freely in a full circle.
After manually freeing the flywheel, look down the drain opening with a flashlight to identify the object that caused the jam. Use a pair of tongs or long-handled pliers to safely remove the obstruction from the grinding chamber, remembering to never use your hands. Once the object is removed, press the reset button on the bottom of the unit, restore power, and test the disposal with cold water running.
The Running Disposal: Addressing Clogs and Slow Grinding
If the disposal runs freely but water backs up into the sink, there is a clog in the drain line beyond the unit. This blockage is often located in the P-trap or the drainpipe, where food particles have accumulated. Try using a sink plunger to create a vacuum and dislodge the material from the pipe.
A non-chemical solution involves pouring a half-cup of baking soda down the drain, followed by a cup of white vinegar. This creates a fizzing reaction that helps break down organic matter. Allow the mixture to sit for about 15 minutes, then flush the drain with hot water. Avoid using harsh chemical drain cleaners, as they can damage the disposal’s plastic and rubber components.
If the unit is running but grinding inefficiently, it may be due to gunk buildup on the impellers or dulling of the grinding elements. To clean and sharpen the components, drop a handful of ice cubes and a cup of rock salt into the disposal while running cold water. The ice and coarse salt scour the grinding chamber and the edges of the impellers, removing residue and improving performance. Running citrus peels through the unit afterward can also neutralize lingering odors.
Safety and When to Call a Plumber
Working on a garbage disposal requires strict adherence to safety protocols. Always ensure the power is completely disconnected at the wall switch or circuit breaker before working on the unit. Never insert your hand into the disposal opening; rely instead on tools like tongs or a wooden dowel to manipulate objects inside.
While many issues are simple fixes, certain symptoms require professional attention.
When to Call a Plumber
- Persistent, major leaks coming from the unit’s body or drain connections, signaling a cracked housing or seal failure.
- A burning smell or visible smoke from the motor, indicating motor failure and requiring immediate replacement.
- The unit is completely dead after checking the circuit breaker and pressing the reset button.
- The disposal is old and requires repeated troubleshooting.