Water Heaters - Water Heater making "jackhammer" noise

Hi All,

We've moved into a new house and we noticed that, in the morning hours, our water heater makes a loud noise that sounds like a jack hammer.

What's even more of a concern is that a few days ago the heater was leaking and I replaced it (thankfully it was covered under warranty). I was hoping that the replacement wouldn't have the same issue but, alas, it makes the noise as well.

My dad thinks it's air in the water line which makes sense since it is very similiar to the sound a faucet makes when it has been off for a long period. He thinks it happens in the morning because everyone is taking showers for work in the neighborhood and drawing from the water line; so the issue is not even the plumbing/water heater in our home.

That theory makes sense but doesn't ease my concerns that I will be replacing this w.h. again in the near future.

Does anyone have any experience with this and an explanation of what could be causing this sound? Is it detrimental to my w.h?

Thanks for any help!

it is most likely not the water heater. the most common problem is a loose/bad washer or o-ring somewhere in your system. do some detective work and see if you can pinpoint the fixture or at least the area that causes the noise. is there a shower, toilet or sink that is used in the morning that might not otherwise be used ? if so start there and turn off the water to one fixture (toilets and sinks) at a time and see if the problem stops. very often it is the fill valve in a toilet or the stop valve for a toilet or sink that is the culprit. also washing machines sometime cause the problem as they, toilets and ice makers have quick closing valves in them and if that is the case, hammer arrestors may help

This happens a lot in houses many service calls for it. Its simply water hammer.

Water hammer - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Water_hammer)

Viddler.com - Simulation of the water hammer effect - Uploaded by jrdul (http://www.viddler.com/explore/jrdul/videos/8/)

Put one of these on the heater side and it should be fine no worries.

Water Hammer Arresters from FAMOUS PLUMBING SUPPLY (http://www.plumbingsupply.com/waterhammerarresters.html)

it will not work if it is not installed close to where the problem is coming from.

why not find and fix the problem rather than trying to cover it up ?

if a new heater is making the same noise as the old one then it is safe to say that it is not the heater causing it