CSLB C-36 Plumbing ContractorFixture and Appliance InstallationEasy
A homeowner reports that their garbage disposal is humming but not grinding, and the motor is getting hot. There are no visible leaks. What is the most common and immediate action a plumber should take?
- AReplace the entire garbage disposal unit.
- BCheck for an obstruction inside the grinding chamber and clear it.
- CInspect the electrical wiring for a short circuit.
- DReset the thermal overload button on the bottom of the unit.
Show answer & explanationAnswer & explanation
Correct answer: D. Reset the thermal overload button on the bottom of the unit.
A humming disposal with a hot motor indicates the motor is trying to run but is overloaded or jammed. The thermal overload button is designed to trip in such situations to prevent motor damage. Resetting it after clearing any potential jam is the first troubleshooting step.
Why the other options are wrong
- A. Replacing the unit is a last resort, not the first troubleshooting step.
- B. While a jam is likely, the thermal overload button has usually tripped, preventing the motor from running even if the jam is cleared. Resetting it is a necessary follow-up.
- C. A short circuit would likely trip a breaker and prevent any humming; this is less likely than a jam/overload.
Garbage Disposal Thermal Overload Reset
A safety feature on garbage disposals that trips to shut down the motor when it overheats or is overloaded, preventing damage.
- Located on the bottom of the disposal unit.
- Must be pressed to restore power after tripping.
- Often trips due to jams or continuous heavy use.
Memory trick: Humming and hot means 'Help Out' by pressing the reset.