Speedy Jim wrote in message ...
Robert Spike wrote:

"HRL" wrote in message ...
"Robert Spike" wrote in message
om...
I just had a new hot water heater installed a week ago. The plumber
recommended an Expansion Tank, and he installed one of those as well.

Everything is fine. However, once my shower is turned off, or a
toilet is flushed and fills back up, I still hear water flowing
through my pipes through out the house for about 30 seconds or so.
Nothing is leaking anywhere, and this behavior did not exist before
the new hot water heater and new Expansion Tank were installed. My
plumber is baffled. He came out and replaced the Expansion Tank
(thinking that was the problem) but it hasn't helped.

Any idea why this is happening? Is it the new Expansion Tank and, if
so, is this normal behavior?

Please feel free to post here, or e-mail me directly at
.

I am baffled why the plumber doesn't know.
Why did he recommend the expansion tank unless you had low water flow?
So now that you have the expansion tank you should get more flow with the
extra supplied from the tank. But after you turn off the valves it takes a
while for it to fill again. If there is a way to turn off the line to the
expansion tank I expect turning it off would eliminate the problem.

If the sound itself is exceptionally loud that is something else.

Since posting my last message, I contacted the Water Company. My home
currently DOES NOT have a Back-Flow device installed, but it DOES have
a Pressure Reducing Valve. They suggested having the plumber inspect
the Pressure Reducing Valve and adjust it if necessary. Is this
consistent with the problem that I am describing? Do these things
need adjusting?

In speaking with my plumber again, he wants to come out and remove the
Expansion Tank so see if that helps the problem. If he does that, and
the problem goes away, what then? How necessary is the Expansion
Tank? The house is 16 years old and has never had an Expansion Tank
before.

A thermal expansion tank is *required* when there is a pressure
reducing valve or backflow preventer installed. So, the plumber was
acting on his best instincts.

One possibility is that the reducing valve is not closing tightly.
This means that once the set pressure is reached, a small amount of
water continues to flow past the valve seat and the pressure slowly
climbs to max street pressure. Easily test this theory with a pressure
gauge. It sure would explain the noise.

Jim


The plumber returned to my home and corrected the problem. I thought
I would post my findings here.

He took a pressure reading and it revealed a reading of 105 PSI. He
tried to adjust the Pressure Reducing Valve but it wouldn't go below
100 PSI. He said this was way too high. He replaced the Pressure
Reducing Valve, adjusted the pressure to 75 PSI and now all is fixed.
Now when I flush a toilet, turn the shower off etc. the water stops
immediately and I don't hear the noise anymore.

Thanks for all the information.