Water heater starts rumbling noise again.

[mxnerd]

Time to replace the water heater? It starts rumbling several months ago and hot water coming out from top hot water release valve.

Then I found the temperature was turn to highest temperature and I turn it down to 120 degree. Flushed the tank and it seems good.

In the past few days the rumbling noise appears again whenever I turn on hot water faucet, not even until hot water coming out, the water heater rumbled and also some hot water coming out from top release valve.

Today I flushed the water again, did not see any metal sediment. Filled the water tank, the water tank rumbled immediately as soon as I turned on the fire via Honeywell controller.

Do I need to replace the water heater? This Bradford lasts just 8 years. The previous GE (I think, can't remember) lasted at least 20 years!

Ideas?

 

[Paperdoc]

The "rumbling" is bubbles of air moving through the tank and pipes. In your first case it could have been steam because the water was much too hot, and you fixed that by turning down the temperature setting. Or, it could have been air that time, too. You have not said the same cause has happened the second time, so I assume you already checked that. The second event may just be air. Sometimes air leaks iinto the system for various reasons and cannot escape easily. You can eliminate it by opeining the hot water tap at the highest point in your system (in my case that would be the sink or tub in the bathroom on the top floor of the house). Open it full to let lots of water flow through, and wait for bursts of air to blow out with the water until the air bursts stop. Then close the tap, and the rumbling should be gone.

For your info, how does air get in? Well, water can dissolve air, but its capacity for air decreases as it get hotter. So when you warm up cold water with lots of air naturally dissolved in it, some of the air escapes from the water and collects in bubbles that cannot be re-dissolved and are trapped in the piping system. In a hot water tank, those will tend to collect in the top if the tank and then be pushed out into the hot water pipes leading to your taps.

 

[mxnerd]

Wow, thanks! That's great info.

I'll try your suggestions, cheers!

 

[fritzfield]

At 8 yrs, the PT valve is probably needing replacement, as well as the anode rod. Probably dip tube and the water heater expansion tank as well. I salvaged my 8 yr old B-W by replacing all of these parts. It was a job, but the thing works great again. I have a B-W Defender 40 gal gas WH.

 

[Paperdoc]

I have had to replace the Press / Temp relief valve a few times on tanks, most often when they start to leak for no reason other than they wore out. Fortunately the water here is very soft and not agressive from a corrosion standpoint, so I've never had trouble with the dip tube or anode rod. My most common reason for replacing tanks over the years has been the old tank itself started to leak.

 

[C1]

Rumbling can also be the result of sediment accumulated in the inside bottom of the heater tank. Such sediment interfers with heat transfer and water trapped between the sediment & heater bottom easily turns into steam. The heater system continues heating because the heat from the tank bottom is not readily transferred to the main body of tank water located above the sediment.

https://www.mrplumberatlanta.com/he...ater-heater-making-a-knocking-rumbling-noise/

 

[mxnerd]

Thanks to @Paperdoc !

After I opened hot water faucet upstair and run it for a while and let the air out, it's been good for a week now, no scary rumbling sound anymore!

 

[Paperdoc]

Good to hear. Thanks for letting us know.