Garbage Disposal Troubleshooting

Stuck Flywheel / Disposal Will Not Run (makes a humming noise)
If the garbage disposal won't turn on but makes a humming sound when you flip the switch, it won't do that for long. That means you have a stuck flywheel and the reset button on the unit itself or the fuse or circuit breaker in your electrical service panel will trip and turn off very quickly. The flywheel is stuck because something is lodged between it or the impeller(s) and the shredder ring.
  • To start the repair, turn off power to the garbage disposal at the electrical service panel.
  • Reminder: Don't ever put your hand down into the garbage disposal hopper (grinding chamber).
  • Take the offset wrench that came with the disposal unit and insert the wrench into the flywheel turning hole in the bottom of the unit. If you don't have the wrench you can pick one up from the hardware store that sells your garbage disposal.
  • Once the wrench is inserted, turn it clockwise to dislodge the stuck impeller or flywheel. When it dislodges, you'll feel the flywheel turn freely.
  • Another approach is to try and use a wooden broom-handle or similar wooden object to free the stuck impeller and flywheel from the top of the unit through the drain.
  • Place the broom-handle into the hopper and against an impeller. Use leverage to try and free the stuck flywheel. As before, when it dislodges you'll feel the flywheel turn freely.
  • Once freed, turn the power back on at the panel but don't turn on the disposal yet.
  • Go back to the disposal and press the reset button.
  • Run some tap water into the disposal and quickly flip the switch on and off turning the disposal on for a short burst. Turn on and off again quickly. That should spin the flywheel and the dislodged obstruction should be washed down the drain.

Leaking Garbage Disposal
Leaks can occur at a number of places on a garbage disposer. Let's take a look at the most common:

Leak at the Sink Flange

  • Turn off power to the disposal at the electrical service panel.
  • At the disposer mount, turn the disposal to the left (counter-clockwise from bottom) to loosen and remove the unit from the mounting flange.
  • Tighten the three mounting bolts.
  • If the bolts are tight, the leak may be caused by failed plumbers putty. Loosen the bolts and push the sink flange slightly above the surface of the sink.
  • Force plumbers putty between the sink flange and the sink, going completely around the flange.
  • Tighten the mounting bolts drawing the sink flange tight to the sink surface. The putty will ooze out. Wipe away excess putty.
  • Reinstall the disposal and turn power back on at the service panel.
  • Check for leaks.
  • Leak at the Dishwasher Connection

    • Tighten the clamp on the dishwasher hose connected to the dishwasher inlet on the disposer.
    • Replace the hose if the hose is leaking.

    Leak at the Discharge Drainpipe

    • Check the bolts holding the discharge pipe to the disposal for tightness.
    • If that does not work, remove the bolts and the pipe and replace the gasket.
    • Reinstall bolts and tighten.

Slow Draining
Slow draining of a garbage disposal can be caused by a number of problems.
  • Assuming you've given the disposal enough time to run and clear the garbage, you probably have a clogged drain line.
  • NOTE: Never use chemical drain cleaners with a garbage disposal! You will damage the disposal and since the chemicals probably won't work anyway, you'll end up with a sink full of toxic chemicals you'll have to hand bail into a bucket and flush down the toilet.
  • Remove the bolts holding the discharge pipe to the disposal.
  • Disconnect the drain trap and remove the trap and the discharge drain pipe.
  • Check for clogs or obstructions.
  • If none are found, the clog lies in the line going into the wall or beyond the vertical pipe going into the wall.
  • Clear the obstruction with a sink auger.