Water hammer distant from closing valves

[FredBaffled]

Hello forum members,

I've read some water hammer threads already on this site, but starting a new one 'cause my situation may be different. We've had water hammer problems come and (usually) go, but they are back with a vengeance. Why now, no idea but maybe irrelevant. A couple years ago had a pair of sealed cartridge arrestors installed on hot & cold supplies that serve both kitchen (about 10ft from arrestor) and clothes washer (about 25ft). Water pressure is about 65psi.

The hammer is a dull but metallic knocking sound with the "knocks" about twice a second and tapering off for a total of a dozen or so distinct knocks. Any fixture anywhere in the house will provoke the hammer - washer, toilets, any sink faucet. Years ago a plumber added a d-i-y air column (see photo), On suspicion it was waterlogged, I drained it but no change in symptoms.


The hammer sound of course travels easily along copper pipe, but both the vibration of the pipes, and the loudness of the hammer, is closest to the area in the photo, where the pipe from the street enters and connects to the meter. The farther from this location, the sound and the vibration (holding the pipe when water is shut off) are both less intense. There are no obvious loose pipes and no sign of a pipe physically knocking another or a framing member.

I figure, my best shot at this is, get a plumber to cut off the air column and the 4 foot "U" of 3/4 copper, then put in a house-size arrestor (Zurn?) or small expansion tank (Amtrol http://www.supplyhouse.com/Amtrol-537-1-537-Diatrol-Shock-Suppressor?gclid=Cj0KCQjwqvvLBRDIARIsAMYuvBEoBK2X5P3zBfP2SxDRnTBNW9s19A6Ra2VhGfRgBF1ftAPqCzWaitYaAiYJEALw_wcB).

Many thanks for sharing your experience that could apply to my situation.

 

[havasu]

Could that pipe be rubbing against the rock anywhere in the picture? If so, that will cause a vibration sound in itself.

 

[frodo]

Could that pipe be rubbing against the rock anywhere in the picture? If so, that will cause a vibration sound in itself.

looks like insulation between pipe and wall would help

 

[FredBaffled]

Thanks for replying. It's hard to see in the photo, but all of the piping visible in the picture is at least several inches away from the foundation wall. The hammer sound seems isolated to the piping itself and the noise doesn't have a sharp metallic sound. The top of that air chamber is well-secured to the beam with the 2 U-clamps.

Since the air chamber doesn't seem to make a difference (there's a ball valve to isolate it), seems to me it would do no harm to take it and the 10 feet or so of 3/4" pipe out of the equation.

 

[havasu]

Does that air chamber still have air in it? If now, you may need to drain down the water until you get a pocket of air to protect from the hammering.

By the way, welcome back Frodo! Next time you are sitting at death's door, make sure your old lady hands the phone to you instead of screening all of your calls!

 

[frodo]

Does that air chamber still have air in it? If now, you may need to drain down the water until you get a pocket of air to protect from the hammering.

By the way, welcome back Frodo! Next time you are sitting at death's door, make sure your old lady hands the phone to you instead of screening all of your calls!

Dude, they had me so high, you would not have understood a damn thing i said

for 5 weeks I was asleep, How come you did not visit? I would have grunted a hello thru my trach tube and peed on my self for you