On 8/15/2010 4:17 PM, TomAZ wrote:
On Sun, 15 Aug 2010 15:56:20 -0500, The Daring Dufas
wrote:

On 8/15/2010 3:27 PM, TomAZ wrote:
I got a new Maytag 40 gallon water heater (HRN4940TN) about 2.5 years
ago. At about the two year mark it started making loud metallic
clanking sounds when heating. Called maytag and played the noises
over the phone and they had no idea. Went to store where I bought it
and they suggested that I had sediment and needed to flush it (which I
did but with no results). Called a plumber who charged me to tell me
that it didn't have sediment and that there was nothing he could do,
claiming that there was a metal rod that ran the length of the heater
that was making the noise. He also said that it wasn't going bad and
that the noise could be ignored. Easy for him to say since he doesn't
listen to it every day. Any ideas? Did I just get a turkey? It
doesn't strike me as a very long lifespan.

That's supposed to be a self cleaning water heater. I wonder if the
noise could have something to do with the baffle that hangs down
through the center of the heater. The next time you hear the noise,
try jiggling the baffle with a screwdriver so as not to burn your
hand or try to reposition the baffle when the burner is off.

TDD
Thanks for reply. If I understand what the baffle is, I don't see how
it can be "jiggled." Seems to be tight as a tick . But that sounds
like what the noise is coming from. Definitely internal, not part of
vent or plumbing or anything else.

Well, the baffle is usually a twisted piece of metal that makes the hot
flue gases swirl around so more heat can be extracted. Most of them I've
seen can be slid out through the top of the water heater. If yours is
tight, it could be that heat is causing the metal to expand and make
noise. If you can lift the vent off the top of the water heater, you
should be able to move the baffle. Perhaps a little mechanical
persuasion with a hammer and pry bar will loosen it up. I wonder if soot
buildup of some kind may have glued it in place and not allowed it to
expand properly?

TDD