Shower in the 2nd bathroom

[greenbaypackersfan]

Hi folks,
My current home has 2.5 bath. The shower and sink in the 2nd bathroom (master as the main) has a clung/thump sound a few seconds after I shut off the sink faucet / or shower. It does not do this in the main bathroom faucet nor shower and only at the second bathroom.
I have read about the water hammering and the technique of solving the possible air bubble that is inside the copper line. I shut off the main water valve and open all the faucets to let the water drain first then lowest point of faucet / closest to the main water valve coming in from the house, then opened up all of the 2nd floor faucets. That didn't solve the problem at all and the clung, or single thump sound came back after I open up the 2nd floor faucet and let it run for awhile.

The sound is sort of *THUMP* follows with a stretching sound somewhere in the attic (as the main bathroom is on the 2nd floor. <attic on a level above.) I went up to the attic to see and no pipes are broken. I can hear in the basement too and wonder if this could leak to possible serious damages in the future?

please help.

[jadnashua]

The hassle with a water hammer is the pipe can move if not anchored, and then it may rub on something long enough to eventually create a hole. It is also tough on washers and hoses. Water hammer occurs when you have a fast closign valve - the water has intertia, and tries to continue to move and any loose pipe can bang against something. The shock wave can propagate a ways, but is normally most noticeable at the valve you shut off since that is the way the water is moving.

What is your water pressure? You may need a PRV to bring it down. The higher the pressure, the faster the water can move, the more this can happen. It normally doesn't occur with faucets...it is more common from things with fast acting valves like washing machines, ice makers, etc.

[greenbaypackersfan]

No, I doesn't happen on my washing machine or the ice maker. It only does it on the 2nd bathroom on the 2nd floor. The master bathroom which is a couple of doors down the hall does not make such sound. It does it on the sink faucet and the bathroom shower when the water is turned off... the loud thump sound is repeative and slowly to die down as time goes.
I thought it has air in the pipes so I did the whole shutting off the main water valve and turn on all the faucet , shower, garden hose etc., but that didn't solve the problem. One other thing someone mentioned was, perhaps I'm turned the the hot water temperature knob too high so after a good hot shower, it does that.

I don't know what's the water pressure in my house, is there a way to check? If the water pressure is too high, would it do it on all of the faucet in my house and not just in 1 bathroom? The master bath is where we use most, and does not have that sound. I'm beginning to think it might be a pipe that isn't being tied down...hence banging on something.

[Terry]

If you have plastic drains, it may be that hot water is expanding the pipe, and then as it cools, it gets smaller.
If the holes are crooked, it may grab as it shrinks.
This the clunk.

[hj]

I would have to hear the sound, because what you think you hear and what is actually happening may be two different things. Water hammer is "instantaneous" when you close a valve and while it is an oscillating sound it happens too quickly for you to hear anything other than what sounds like a single event. Air in the pipes, which by the way is an impossibility if you have had the faucets open, would PREVENT the sound not cause it.

[greenbaypackersfan]

yes sir! You are correct on both ends. I found what is was generating the sound after shutting off the faucet each time.
I had an idea a couple of nights ago, so I decided to give it a shot. I first turned the faucet on (the bathroom that has the problem.) but with COLD water only! And no sound, then I turned it to HOT, and boom there goes the sound. Same goes for the shower on that bathroom.
I realized it's the HOT WATER pipe that produces the sound, and realized I kept my HOT WATER TANK temperature a bit on the high side, so I gave a few good shot and turned down the hot water temperature. BOOM! solved the problem.

I thought it has air in the pipes so I did the whole shutting off the main water valve and turn on all the faucet , shower, garden hose etc., but that didn't solve the problem because it WAS NOT the problem.

You are corrrect sir, no way I could have air in my tube.

If you have plastic drains, it may be that hot water is expanding the pipe, and then as it cools, it gets smaller.
If the holes are crooked, it may grab as it shrinks.
This the clunk.
Terry

[hj]

I am at a loss as to how the "hotter" water could have produced the sound, but if your adjustment fixed the problem then you are okay, at least for now.

[greenbaypackersfan]

^ I tried turning the HOT WATER HEATER down a couple of noticed and noticed the sound went away. But the water is then WARM, as my wife likes to take HOT showers. I then turned a couple of notches back to the HOT side and noticed the sound is there when someone takes a long shower....

[Terry]

I have had bathrooms, where I've had to cut drywall, and find where the pipes go up through the floor.
A little work with a sawzall allowed me to cut away enough wood, so that the pipes didn't bind against the wood.

Or, you can just let it go, and figure it's one of the noises a house makes.
It can be annoying though.
After going back a few times on service calls, you would be surprised at how crooked some of the plumbers can drill a hole sometimes.

[greenbaypackersfan]

I have had bathrooms, where I've had to cut drywall, and find where the pipes go up through the floor.
A little work with a sawzall allowed me to cut away enough wood, so that the pipes didn't bind against the wood.

Or, you can just let it go, and figure it's one of the noises a house makes.
It can be annoying though.
After going back a few times on service calls, you would be surprised at how crooked some of the plumbers can drill a hole sometimes.

^ completely agree. I will have to find some time to cut the drywall and see if the pipes are hitting against the wall. I believe this may be the case or could easily been the pipe expanding.
I do not mind the noise as long as it's not doing any harm.