water heating banging - few question

[todthebod]

Hi! This site looks awesome! I hope I can get a few questions answered and maybe provide some help in some other areas since plumbing is not my forte.


I have a banging water heater and I've read all about the sediment that causes it. I want to make sure that's what it is before I invest in another heater. It's 10 years old and I probably drain it about every year and a half on average. It started banging one morning a few days ago but only when one of our 3 toilets are flushed and it bangs while the toilet is filling. I tried draining the heater. That didn't work so I tried flushing the heater (drain open and supply open). The banging was constant while water was supplying the heater. So I have banging when any of the 3 toilets are filling or when I'm flushing the water heater and not when any other faucets or appliances are being used.

I'm confused at why the banging is only occurring from toilets filling and not with anything else. Shouldn't it be banging when a faucet or appliance is using hot water?

 

[Redwood]

Water heater banging typically is caused by the water heater being heated through a large amount of sediment where pockets of water in the sediment turn to steam and burst out of the sediment. It kind of sounds like pop corn...

I think you have something else going on.

Are you on a municipal water supply or, a well?

What brand of fill valve do you have in your toilets?

Are the angle stop valves for the toilets fully open?

Does the noise change when you turn the angle stop valves for the toilet when the tank is refilling?

 

[user 4883]

I agree with Redwood, sounds like you have a different type of problem.
Two things come to mind.
1. the dip tube has broken off and is floating around inside the heater or
2. the anode rod has broken into pieces and is floating around inside the heater.
Not sure how to check the anode rod but, to check the dip tube, you will have to disconnect the supply line and stick your finger in there to see if it is still intact.

 

[todthebod]

Ok thanks for the replies so far. I turned off the supply for the water heater and began draining to check it out. While I was doing this I opened up the valve for the garden hose and the banging was full force. Does this eliminate my water heater as the culprit?

I'm on municipal water supply. The banging seems to happen when there is a large flow of cold water like open garden hose, toilet, or multiple valves at the same time. The toilet valves are fully open and I can get the noise to quieten by closing the toilet valves by about 50%.

 

[Redwood]

The fact that the banging occurs with cold water usage kind of rules out the water heater as a problem area....

Do you have a hot water recirculation system on the water heater?
A check valve banging perhaps?

 

[todthebod]

I know it's been awhile so I just wanted to update in case anyone else has this problem. I did a lot of things tracing this problem.

Drained lines to make sure no air was in there. Finally gave up and had a plumber come out. He put a new regulator in since the water pressure was 100-120. That didn't work so he made sure all the pipes were strapped down. That didn't work so he put arrestors on the cold and hot water lines and of course that didn't work. $700 down the drain LOL. Then the plumber looked at the water meter and it was jumping around making a weird noise so I convinced the water company to come out and check it. It was good I saw it for myself. So now I'm bumfuzzled as well as the plumber and the water company. After I calm down I just start digging up my line going from the house to the road. About five feet out I see some time of on/off valve. That was weird just to bury that with no access. It felt good so I dug a little past it and there it is. A damn regulator hidden in the ground. I replace it with some pvc and all is well. What an experience!

 

[inspectorD]

Well, good thing you kept at it and kept digging. As in all building, you just never know what someone else did when they install something.
Thanks for sharing!!