I just installed an AO Smith 50 gallon hot water heater in my basement in May of 2021. It has been working great for the past half year or so. Today, I found that I only had luke warm water for my shower. I went to my hot water heater and I did not hear it heating the water in the tank.

I flipped the hot water heater circuit off and on and it still did not heat the water. I then turned the circuit off, took the panel off the hot water heater and hit the reset button. I then flipped the circuit back on and it started to heat the water in the tank. After about a minute of the water being heated, I noticed a very loud grinding/buzzing sound that was coming from my circuit breaker panel. I quickly shut off the circuit and the buzzing immediately stopped.

I checked to see if the wiring was secure in the water heater. I found that it was. I then turned the circuit breaker back on and again it was fine for about a minute and then I heard the loud buzzing sound coming from the circuit breaker again so I shut it off.

I was looking for advice to see if this might be an issue with the hot water heater, or would it be an issue with my circuit breaker panel. I have never heard this buzzing sound on my circuit before today with my old or current water heater. It appears that my water heater is under warranty but did not want to go through the hassle of installing a new one again if that was not what was causing the issue.

Below is a link to google photos showing a video that I took of the grinding sound.


Update 1/5/22 I just replaced the circuit breaker and I will be replacing the thermostat tomorrow. I found that the top of my hot water heater is hot but the bottom is ice cold. I used a multimeter and found that there was no continuity in the bottom heating element. Is that always indicative of a failed heating element and if so, does that mean that my thermostat is probably fine?

Update 1/6/22

I just replaced the top thermostat and the bottom heating element. I think I found the true issue now. The bottom heating element is heating now. The issue is the the bottom heating element is not shutting off. I have the bottom thermostat set to 120 degrees F. When I used an infrared thermometer, I found that the tank next to the heating element is already up to 150 and the water coming out the top is 160. Far above what I set it to.

Would I just need to replace the bottom thermostat and I should be good? How would I make sure the thermostat isn't grounded with a multimeter? I highly doubt this would be an issue since this water heater is less than a year old but I wanted to make sure.

  • 2
    Buzzing sound from your panel could mean that a breaker is failing or even sparking. Can you take the cover off the panel and inspect the inside?
    – user78790
    Commented Dec 26, 2021 at 6:44
  • 2
    What brand breaker/breaker panel? How old? It's very unusual for a breaker to make that sound. Most likely a defective/failing breaker. Commented Dec 26, 2021 at 7:26
  • 1
    Well you tell your friend that I think the thermostat is the one electric component in the circuit that is not suspect. Commented Dec 26, 2021 at 22:35
  • 1
    I see several possibilities. First check the breaker rating and be sure it is properly rated for the heater. Some of the older magnetic breakers buzzed when the load was close to there capacity. Replacing the breaker would solve that. It is also possible you have an element that has corroded and is leaking current to ground through the water. This would cause a rise in current. Use a clamp meter and measure the current in each phase and see if it is stable and in rating.
    – Gil
    Commented Dec 26, 2021 at 22:46
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    @JustinTodd -- yeah, that means your bottom heating element is dead as a doornail, probably burned itself out due to excessive sediment Commented Jan 6, 2022 at 5:05

1 Answer 1


Replaced the buzzing circuit breaker and then also the upper and lower thermostat and burnt out lower heating element which fixed the issue!

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