Guys,
I think that you have given me some ideas. I had wondered a bit as I was
draining the tank about the outflow size of the drain, but figured "it must be
right cause that's the manufacturer's own part". Now I can see that it's not
maybe correct or even the best thing, even if they put it on.

I don't think I have heat saver nipples. I just checked. All that I can see
coming out of the female couplings on the tank are what look like short,
standard nipples. To this is screwed on a copper pipe adapter that has a
female threaded opening (pipe threads) and hex flats on it. That, then
attatches to the hot two copper pipe lines above with the usual methods of
copper pipe and sweat on couplers.

Thanks,

Danny

HerHusband wrote:

Danny,

I moved into a new house almost a year ago. From the first day that I
moved in, the Hot water tank would rumble. It's certainly an older
(gas) unit and will need replacement in the near future, but I'd still
like to try to figure out variouis reasons that it might be rumbling.
It used to rumble when you'd open a tap or fill a bath,
but it seems not to do it at those times so much now.

I think sediment build up is the most common cause of water heater noise.

However, if you have "heat saver" nipples coming out of the top of your
water heater, you may want to check or replace those too.

We installed a new electric water heater, with new "heat saver" pipe
nipples. Anytime we used hot water we would get loud rumbling noises from
the water heater. The more flow, the louder the noise. Running the bathtub
faucets was the worst.

Anyway, I just installed a circulating pump on our system, and replaced the
heat saver nipples with regular brass pipe nipples. The noise is gone!

I researched this a bit and it turns out that the little balls or flappers
in the heat saver nipples can rattle or vibrate as water passes through
them. It's amazing how much noise they can make.

Something to check...

Anthony