Confused on which way to go

[Jonathon Bennett]

Hey guys and Gals. If someone can give me some guidence, it would take a huge weight off my shoulders.

Essentially my pipes are banging in a two story condo, whenever any fixture is turned off. Found out from the previous owner. That up until 10 years ago the condo had PB pipe. When it ruptured all the pipes in the condo were changed to copper. Apparently the pipes have been banging for ten years. (yeesh) So this is where I'm at. Pipes bang at the same place when any fixture is turned off (but given it is a two story condo. I cant narrow the exact location down since its somewhere near the stairwell. So instead of tearing the walls apart, I installed an air chamber @ the hot water heater. Well, this worked for about two days and then the banging returned. (Figured it just flooded) I Checked the pressure and it is @ 60 psi. (which seems normal) If I decrease it to 40 or so psi by closing the ball valve the banging will go away. I guess my question is. Since the pressure seems normal. Is it probably just a loose/unstrapped pipe? And even if that is the case, since a simple air chamber made it go away for a couple of days. Would taking it out and replacing it with either an arrestor or expansion tank be the way to go?
Any ideas would be greatly appreciated. Since, short of tearing the walls down, I really don't know which way to go.

Thanks all

[Barry Adair]

1. i'd try injecting canned expanding spray foam too encapsulate pipe in and behind suspect accessible plumbing escutcheons
2. if this doesn't resolve issue ultrasonic inspection can isolate water hammer location(s)
3. carefully drill 1/4" hole through gypsum board/plaster at any identified locations too avoid puncturing the pipe(s)
   inject canned expanding spray foam too encapsulate pipe
4. once completely cured and tested patch hole and use plumbing as usual

[Jeffrey R. Pope]

You may have some unsecured piping, but have you considered installing hammer-arrestors? No special tools required...

[KEVIN WOOD]

There are now quick fixes for water hammer in plumbers mags.
They are designed to install under the sink to the main shut off for each fixture. If you can isolate which one by purchasing the unit and testing the lines you are good to go.
You do not need a plumber to do this kind of work since it is part of a threaded flex braid steel line to the hot and cold with the water hammer chamber attached.

[Jonathon Bennett]

Originally Posted by jpope

You may have some unsecured piping, but have you considered installing hammer-arrestors? No special tools required...

Thanks for the reply Jeffrey. Yeah, actually I did. I put them upstairs at the washer. Thats another funny thing. It seemed after I installed them, the knock/banging seemed to be worse/harder. Also, to reiterate the situation, regardless of the fixture, all cold lines hammer when shut off. However, if I go out to the main ball valve and close it half way, the hammer is gone. Pressure is lowered somewhat, but still O.K. However, it's a small condo with terrible insulation. So it prolongs things like toilet fills. (Since it adds another 20-30 seconds)

[Jonathon Bennett]

Originally Posted by kwood

There are now quick fixes for water hammer in plumbers mags.
They are designed to install under the sink to the main shut off for each fixture. If you can isolate which one by purchasing the unit and testing the lines you are good to go.
You do not need a plumber to do this kind of work since it is part of a threaded flex braid steel line to the hot and cold with the water hammer chamber attached.

I Get what your saying Kevin, and truly appreciate your input. The funny thing it's every cold fixture that bang. (i.e. every sink, every toilet, tub/shower, washing machine, dishwasher, even the outdoor hose spigots. I'm gonna try and post some pics. so you all can see the set up. But like I said, when I sweated in an air chamber (cold line in to hot water heater in front of valve) it went almost completely silent. But just for a couple of days. After that the noise resumed. I figured, it being a simple chamber vs an arrestor, it probably flooded and became useless.

[Jonathon Bennett]

Originally Posted by badair

1. i'd try injecting canned expanding spray foam too encapsulate pipe in and behind suspect accessible plumbing escutcheons
2. if this doesn't resolve issue ultrasonic inspection can isolate water hammer location(s)
3. carefully drill 1/4" hole through gypsum board/plaster at any identified locations too avoid puncturing the pipe(s)
   inject canned expanding spray foam too encapsulate pipe
4. once completely cured and tested patch hole and use plumbing as usual

Just when I thought MacGyver was dead. I like the way you think. And I would have never thought of that remedy. So big kudos. Here is the possible major problem with that though. I'm gonna try and post a pic. But he noise seems to be coming from the area above the bottom landing. Where the 1st floor ceiling extends. In other words, it seem to be where the pipes run up the studs in a void area. Where about 3 feet are concealed by the first floor ceiling, that serves no purpose, other than the concealment of A/C ducts. (If that makes sense) Love your insight, and hope you as well as Jeffery and Kevin will check in on this thread. Pics,I know would help immensely. Just so I can exclude it though. It couldn't be possible that the discharge line would be banging. (Right)
Thanks a million, And I hope you follow this with the forthcoming pics

[KEVIN WOOD]

According to what you say. You should be able to put a pressure reducer on the main going to the Hot water tank.
10 PSI reduction may get rid of the water hammer.

It takes 0.434 psi to raise water one foot. Conversely, one psi will raise water 2.31 feet. If water enters the basement at 60 psi static pressure, there will be 60 psi pressure near the basement floor. To move up through the basement, through the first floor, and to the shower on the second floor, we might have to push the water up 20 feet. This would result in a pressure loss of between 8 and 9 psi (20 X 0.434).
42 psi is what you will have left over.