Plumber Bummer!?

[Dale Thompson]

Help! My daughter and son-in-law have a home which is about three years old. When I was down there this weekend, they claimed to have a "funny" noise in their plumbing when they shut off a faucet or, especially, when their toilet valves shut off. It also happened when their automatic lawn sprinkler system shut off. They said that it was "water hammer" but I don't think that either one of them knows what "water hammer" is. Anyway, the sound doesn't happen every time a valve is turned off quickly. When I listened to the sound, I didn't write it off as "water hammer". That is a "clunk" or a "rattle". I didn't detect any of that either upstairs or when I was down in the basement.

The sound was more like a "valve moan", for lack of a better term. I remember hearing it with the old style toilet valves as they were shutting off. Anyway, I secured the few pipe runs in the basement which were even remotely loose. That didn't help. Also, the local building codes don't require those "air cushions" which are supposed to absorb "water hammer". They were NOT installed. Could that be the problem?

The sound is NOT coming from the closing of the toilet valves. I spent so much time this weekend with my face in a toilet that I thought that I was back in college! I'm stumped!

Dale T.

[Steve Clardy]

Sounds like the plummer gremlins are in there Dale.

I am not a plummer, and not going to be one.
I can plumb two water joints and have at least one leak.

Sorry for the Non-help here Dale.

[Lee Schierer]

Securing loose pipes is not a true cure for water hammer. You need to have shock absorbers if you are going to have high pressure, high flow rates and fast closing valves. You have to dissipate the momentum of the water to prevent damage. This can only be done with a properly sized and installed water hammer device as close to the offending fast closing valve as possible.

The fact that the sprinkler system causes this problem is due to the presence of a solenoid valve in the water line. This valve will close quickly when de-energized and produce water hammer. Some faucets with loose seats can also cause water hammer as they flutter. Tighten the seats and install water hammer arrestors.

Reducing the water pressure can also help.

[Dennis Peacock]

Like Lee stated....I'd put in a pressure regualtor from the main supply line and drop the water pressure to about 40 PSI. I have one installed to get my water pressure down from about 100 PSI to 40 PSI....It's amazing how much longer your plumbing seals and valves last when you drop the water pressure.

[Dale Thompson]

Thanks guys,
Dennis, I'm not sure that dropping the pressure is an option. They are on city water and I don't think that the pressure exceeds 45 psi at the entrance.

Lee, does this mean that I have to put a "damper" close to each of the potentially offending valves? Is there a compromise somewhere for guys like Steve and I who can create three leaks for every two that we attempt to sweat? Also, the "problem" seems to be as frequent with the hot water as with the cold.

This is REALLY important because I'm thinking of putting running water into my own house within the next 5-7 years. WELLLL - maybe I'll hold off for a bit. Who needs the aggravation?

Dale T.

[Bill Turpin]

Water hammer devices need to be as close as possible to the valve. It is the moving water that suddenly has no place to go that causes it. There should be one at every tap, both hot and cold. WH devices or riser pipes in the wall trap a large air bubble which compresses under the hydraulic pressure of the moving water.

Bill in the rain soaked WNC mountains
This our third hurricane aftermath. Can't it be somebody else's turn!

[Michael Perata]

Bill

I have always put WH shock absorber devices at the furtherest point from the water service. Occassionally needing two if the house goes in two directions from the water service.

They should also be in a very accessible place because they wear out.

[Chris Padilla]

Several of my DIY plumbing books say the WH device should go nearest the device that has the problem.

The WH device can be as simple as tee pointed up and capped with a length of line. You just need to drain the line "every so often" to fill it back up with air.

Also, all lines should be well secured with foam/plastic pieces perferably.