When you turn on your garbage disposal, it should make a grinding noise as it breaks down food waste. However, if you hear a humming or buzzing sound instead, it may indicate that something is wrong. The source of the humming sound is the motor trying to turn the impellers but failing due to a blockage or malfunction.
In some cases, the garbage disposal will not spin but stay humming. Sometimes, the disposal will work but is accompanied by a humming noise.
Quick troubleshooting steps to identify the problem
The first step in fixing a humming garbage disposal is to identify the problem correctly. There are several reasons behind humming, which are caused either due to obstructions inside the garbage disposal or due to electrical problems. Identifying this is crucial to fixing the buzzing noise. Here are the steps to do this;
- Turn off the power to the garbage disposal
- Manually rotate the garbage disposal blades using a hex wrench. If the blades are stuck, the humming noise is due to obstructions inside the garbage disposal.
- If the blades move freely without resistance, this is an electrical problem.
Once the problem is identified, select the matching troubleshooting methods listed below;
Reasons for humming and their solutions
Given below are the possible reasons why a humming/buzzing noise is coming from your garbage disposal, and the step-by-step guide to fix them.
1. Stuck or jammed impellers:
Impellers are responsible for breaking down food waste in a garbage disposal. If they become stuck or jammed, it can prevent the motor from functioning correctly, causing a humming sound.
This is the most common reason for garbage disposal’s humming or buzzing sound.
Here is how to fix this;
- Turn off the power supply to the garbage disposal and disconnect it from the sink drain.
- Locate the hex-shaped hole at the bottom of the garbage disposal and insert the special garbage disposal wrench or pliers into the hole.
- Use the wrench or pliers to manually rotate the impellers back and forth to free up any stuck debris that may be causing the impellers to jam.
- If the impellers are still stuck, try using a long wooden spoon handle or similar object to manually rotate the impellers.
- Once the impellers are free, reconnect the garbage disposal to the sink drain and turn on the power supply to see if the buzzing sound has stopped.
Here’s a detailed guide to unjamming a stuck garbage disposal for further reading.
2. Electrical problems:
As with any electrical motor, a garbage disposal can hum if there are loose or faulty electrical connections, faulty wiring, or a tripped circuit breaker.
Here is the solution;
- Turn off the power supply to the garbage disposal by unplugging it or turning off the circuit breaker that controls the unit.
- Inspect the wiring inside the garbage disposal by removing the cover plate at the bottom. Make sure that the wires are connected, and the wire nuts are tight.
- Turn it on
- If the electrical issues cannot be resolved or if the humming sound persists, it may be a sign of a more severe electrical problem, and you should contact a professional technician to diagnose and repair the issue.
3. Overheating:
If a garbage disposal is used for an extended period, it can overheat, causing the motor to stop working correctly and emitting a buzzing sound.
Here is the fix;
- Turn off the power supply to the garbage disposal and wait for about 10-15 minutes to allow it to cool down.
- After the cooling period, press the reset button located on the bottom or side of the garbage disposal.
- Turn on the power supply to the garbage disposal and listen for any humming sounds. If the buzzing sound persists, it may be a sign of a more severe problem, and you should contact a professional technician.
4. Mechanical issues:
Mechanical issues, such as worn-out bearings or misaligned parts, can also cause a garbage disposal to hum.
It is nor practical to replace the motor of a garbage disposal. This is going to cost you more than a new disposal. So if the motor is old and worn out, my suggestion is to replace the entire garbage disposal unit.
5. Motor overload due to clogged drain or pipes:
If the drain or pipes leading to the garbage disposal become clogged, it can prevent water from flowing correctly. This causes water to stand inside the disposal thus adding more load to its motor. As a result, the motor will make a humming noise.
To fix this;
- Turn off the power supply to the garbage disposal and use a plunger or a drain snake to manually clear any blockages in the sink drain or pipes.
- Once the blockage is cleared, reconnect the garbage disposal to the sink drain and turn on the power supply to see if the humming sound has stopped.
6. Low voltage:
A garbage disposal requires a specific voltage to function correctly. If the voltage is too low, it can cause the motor to hum instead of running correctly.
What you need to do is;
- Use a multimeter to test the voltage supply to the garbage disposal.
- If the voltage is too low, contact an electrician to address the issue.
7. Faulty capacitor:
A capacitor is responsible for storing electrical energy and releasing it to the motor to help it start. If the capacitor is faulty, it may cause the motor to hum instead of starting correctly.
Unfortunately, the motor of the garbage disposal comes sealed, so it is impossible to access its capacitor without causing permanent damage to the water-tight seals. If the capacitor is at fault, there is no fix other than replacing the entire garbage disposal unit.
Importance of addressing the humming noise
If you ignore the humming of your garbage disposal, it can lead to several problems. The most immediate issue is that the disposal will not function correctly, and you will not be able to use it to dispose of food waste. Over time, the humming sound can become louder and more persistent, which is a sign that the problem is getting worse.
If the humming is due to a stuck or jammed rotor, ignoring the problem can cause the motor to overheat, which can lead to permanent damage. Additionally, a jammed or stuck rotor can cause damage to the blades of the disposal, which can make it even more difficult to repair or replace.
If the humming is due to electrical issues, ignoring the problem can cause the electrical components of the motor to fail, which can be dangerous. Faulty wiring or loose electrical connections can cause sparks or even electrical fires, which can be hazardous to your home and family.
In summary, ignoring the humming sound from your garbage disposal can lead to more significant problems, including motor damage, blade damage, and electrical fires. It is best to address the issue as soon as possible to avoid further damage and ensure that your disposal functions correctly and safely.
