On Oct 13, 9:20*am, "Sac Dave" wrote:
"DerbyDad03" wrote in message

...





I know about water hammer - the loud noise associated with a rapidly
closing valve causing the water to slam inside pipes causing them to bang.
I also know most of the solutions - arrestors, expansion tanks, securing
pipes, draining the pipes, etc.

The water hammer I'm experiencing is different.

*- Instead of a single loud bang, I get a rapid fire dull
thump-thump-thump almost like the rat-a-tat-tat-tat of a machine gun.
*- They happen when just about any faucet, toilet, shower, appliance, etc.
is turned ON or OFF.
*- When a device is turned ON, I'll get 4 or 5 rapid thumps lasting a
second or two.
*- When a device is turned OFF (even slowly turning off a faucet) I'll get
anywhere from 20 to 50 rapid thumps lasting 3 - 7 seconds.
*- It happens with both hot and cold water, single valve devices or dual
faucet fixtures.
*- It happens 85% - 90% percent of the time.
*- I have drained the system and refilled it. I thought it helped, because
it didn't happen for a few hours, then it started again. It may have just
been the 15% - 20% of the times when it doesn't happen.

Anybody heard of this type of water hammer?

*I had the same sort of thing more like a tapping . No one could figure it
out ( and I'm A plumber) What it turned out to be in my case. On the hot
water tank the two nipples that screw directly into the top of the tank they
are actually small check valves there is a small marble inside that controls
the flow direction . For some reason one of these started vibrating ( supply
to house side) I have never seen one of these before ( I just do commercial
plumbing) I just went and bought two Dielectric nipples without a check
valve and that took care of it. I could not figure where the sound was
coming from it sounded like the pipes were rattling . Anyway that might a
your problem . The sound did get worse at night I'm guessing because of
thermal expansion in the hot water side. I have replaced / installed *a lot
of Hot water tanks but have never seen these check valve nipples . I would
never use them or recommend them. You can just take the marble out easy to
tear apart.- Hide quoted text -

- Show quoted text -

Thanks, but I don't think that's my problem. I installed the water
heater in my house and as far as I know they aren't any "check valves"
on the water tank - unless they came with the unit.