Vibration when water heater fires up

[quaco]

First post here. Thank you for the membership.

BACKGROUND
I have an AO Smith 50-gal water heater. It's about 10 years old, but hasn't had any real problems thus far. I had was having issues with error codes (wouldn't stay lit, faulty thermostat I believe), so I called the company. Since I also had a torn burner screen, AO Smith actually sent over a plumber to fix that and the other problem free of charge, since apparently the burner I had had been recalled. That was nice!

But ever since then, when I turn on hot water and the water heater fires up (piezoelectric starter BTW), there is a vibrating/humming for a few seconds. I sat next to the water heater, and it's definitely something in the burner area vibrating.

RECENT
I called AO Smith again (since I had good luck the first time) and the guy suggested that it needed an "arrestor box" to stop the vibrating. I'm in CA, and he said that that's a common problem for CA water heaters since they have more environmental safeguards which (not sure why) run into these vibration problems. Is he thinking it needs to be tied down for earthquakes? Maybe he misunderstood what I was saying? I'm wondering if when the guy replaced the burner screen, he might not have tightened it fully, so it's vibrating.

Here is a video of the sound that happens when it fires up. See what you think! You might need to turn up the volume. It's quiet in the video, but it definitely vibrates through the pipes in the house.



Thank you again. I look forward to looking around the forums.

 

[breplum]

It may be the corrugated gas flex line outside the water heater.
Try adjusting any bends it may have. I've also seen similar sound when 3/8" gas flex was used instead of 1/2" flex.
See if slightly closing the gas valve affects the sound.

 

[Twowaxhack]

I’ve heard that before and the answer was a new burner assembly.

 

[quaco]

It may be the corrugated gas flex line outside the water heater.
Try adjusting any bends it may have. I've also seen similar sound when 3/8" gas flex was used instead of 1/2" flex.
See if slightly closing the gas valve affects the sound.

Thanks I'll try this

 

[quaco]

I’ve heard that before and the answer was a new burner assembly.

This is a new burner, just installed. It wasn't making the sound before. Maybe he didn't install it quite right? or maybe it's defective?

 

[Twowaxhack]

Maybe defective in some way. I’ve heard that sound before and the fix was a new burner assemble.

If it doesn’t bother you, I’d just leave it.