Water hammer

[CMV]

Way off topic - sorry - but figured you guys would know this & get me going in right direction....

Replaced washing machine a couple months ago and ever since have had a bad water hammer effect in our upstairs bathroom. Always had a tiny one, but now it's unbearable. Used to, could hear the pipes make one soft "thud" when a downstairs toilet stopped flushing but it was very seldom. And one small noise & that was it. Now, after putting new machine in, those pipes make all sorts of racket pretty much whenever it is running. Oddly, even just when it's washing - not cycling water on/off - there's still noise. Running the shower in master bathroom (downstairs) makes the one upstairs make all sorts of racket now even if washing machine isn't doing anything. Much louder now and continual banging noises when it happens vs just one soft thud occasionally when something closed a valve.

SO I bought a set of water hammer arrestors from Lowes: https://www.lowes.com/pd/Sioux-Chief-Copper-3-4-in-Hose-Pressure-Reducing-Valve/3172327 they're pretty small but just screw in between the faucets and washing machine hoses. That helped some, maybe cut it 25%. In addition to that I tried partially closing the faucet valves to the washing machine going as far as to just let them trickle and take 20+ min just to fill. Also tried partially closing the main water valve basically reducing water pressure to whole house a little bit.

But really the only thing that makes it stop is to go upstairs and run some water in the shower when it happens. Turn that shower off, and it starts right back up in a minute.

The upstairs shower is the farthest plumbing from the main water line and hot water heater. That's only place in house that has this water hammer issue. Opening a sink or flushing toilet in that bathroom doesn't seem to do anything to stop the water hammer - only the shower. It's one of those one-piece fiberglass bathtub and shower stall type things too, so seems it would be pretty difficult to get to the pipes going to the shower valve but those are the ones making all the noise.

Not sure what to do next. Hate to replace a brand new washing machine, but I suspect it is somehow the culprit as this happened immediately after putting it in. I saw some larger arrestors/pressure tubes at Lowes that get sweated into copper pipes. Maybe that's what I need and the ones I bought are too small? If so, no idea where to put it - near the noise or near the main valve? Plenty of room behind the washing machine so I could buy a few more of what I have and just put a few in series if that would do anything - they look like they would thread into each other so I could make a chain of them in that would shut these pipes up! Instructions said could be installed in any direction.....I installed with the tubes pointing straight up if that matters.

 

[ch1ch2]

Are your water lines at the washing machine tightly affixed to the wall?
Seems to me most water hammer issues have the pipes moving. Less movement less hammer.

 

[CMV]

At the washing machine, yes. I would suspect if I tore into drywall in upstairs bathroom would find those pipes not well secured.

Washing machine is on first floor in a laundry closet in kitchen. Pretty much right behind where my main water valve is - within a few feet. All the noise happens as far away from that area as you can get.

 

[ch1ch2]

Been a while since I retired and I have forgot a lot, and I forget more everyday.
As I recall.... water has mass and that mass can be very heavy. When a valve shuts fast, that mass has to stop moving fast. That causes the pipes to shake or move causing the hammer noise.

 

[oosik]

The hot/cold water pipes going into my wash machine close with an audible clunk when the machine opens/closes its valves. It's not objectionable - just noticeable. The water moving thru the pipes has its movement stopped so rapidly - the mass slams into the valve and will cause the pipes to shake slightly. Will also make the "clunk" sound.
There are water hammer solutions that can correct this condition - if it's objectionable.

 

[PILOON]

Actual devices are sold for water hammer problem,
however,
A water hammer 'silencer' is really simple to make.
It is a section of pipe in which there is trapped air which absorbs the shock wave so to speak.
Somewhere in the water line near the washer cut, insert a 'T' and add a capped short ,6 inch or so length of pipe.
Note that short length must be vertical and empty after soldering is finished.
That pocket of air will act as a shock absorber to lessen or eliminate the bangs.

They also sell commercial units to do this but as described U can fabricate one.(also need vertical installation)

I am on a well and my pressure tank being a bladder type unit takes care of water hammers.

 

[Raspy]

CMV,

It's possible that you have water hammer risers in the wall behind the washer. These fill up with water eventually and lose affect. So the first thing to try is to drain the house. Shut off the water where it enters the house, open the outside fixtures and inside sink and shower valves. Disconnect the washer hoses and open their shutoff valves to allow air to go into the system. This will get air to all of these in-the-wall arresters, if they are there. Turn any electric water heaters off and gas water heaters to pilot while doing this. Then re-fill the house and see if that helped. If not, get bigger arresters that screw on at the hoses. The little ones that are about the size of a thumb are often not big enough. You should also have an accumulator on the cold side of the water heater. These can help with hammer as well as thermal expansion. If you already have one, make sure its pressure is a little below the street pressure while you have the house drained.

To re-fill the house, turn off the outside hose bibs and just crack the inside faucets. Then turn on the main shutoff part way. Close the faucets as they begin to run with water only. Then open the main all the way. Start the water heater(s). Then see if the water hammer is gone.

 

[ch1ch2]

CMV,

It's possible that you have water hammer risers in the wall behind the washer. These fill up with water eventually and lose affect. So the first thing to try is to drain the house. Shut off the water where it enters the house, open the outside fixtures and inside sink and shower valves. Disconnect the washer hoses and open their shutoff valves to allow air to go into the system. This will get air to all of these in-the-wall arresters, if they are there. Turn any electric water heaters off and gas water heaters to pilot while doing this. Then re-fill the house and see if that helped. If not, get bigger arresters that screw on at the hoses. The little ones that are about the size of a thumb are often not big enough. You should also have an accumulator on the cold side of the water heater. These can help with hammer as well as thermal expansion. If you already have one, make sure its pressure is a little below the street pressure while you have the house drained.

To re-fill the house, turn off the outside hose bibs and just crack the inside faucets. Then turn on the main shutoff part way. Close the faucets as they begin to run with water only. Then open the main all the way. Start the water heater(s). Then see if the water hammer is gone.

Thank you Raspy, though I am not the OP, knew there was something I was forgetting. Those water line risers are part of code for most new two story construction. My old houses did not have them and my current house is one story. My memory is OK, its my recall that does not work.

 

[Raspy]

Actual devices are sold for water hammer problem,
however,
A water hammer 'silencer' is really simple to make.
It is a section of pipe in which there is trapped air which absorbs the shock wave so to speak.
Somewhere in the water line near the washer cut, insert a 'T' and add a capped short ,6 inch or so length of pipe.
Note that short length must be vertical and empty after soldering is finished.
That pocket of air will act as a shock absorber to lessen or eliminate the bangs.

They also sell commercial units to do this but as described U can fabricate one.(also need vertical installation)

I am on a well and my pressure tank being a bladder type unit takes care of water hammers.

These stand pipes only work for a while because they fill up with water and have to be re-charged with air after a while. Note my post above. They are commonly installed behind the washer valves while building and are about 12" long. The problem with the bladder tank acting as a water hammer device is that it is typically at the wrong end of the pipe and far from rapidly closing appliance valves. It's the slug of water after the pressure tank that causes the hammer as it is abruptly stopped by an appliance valve, or sink valve. Those pressure tanks will control the thermal expansion and reduce pump cycling though.

 

[jimainiac]

It sounds like you have very high water pressure. Are you on a municipal water system? Do you know what your actual water pressure is? We once lived where we were on town water, and the pressure was quite high, resulting in banging pipes. The water hammer arresters help, but I ended up adding an adjustable pressure reducing valve near where the water line came into the building. I was then able to turn the pressure down to an acceptable level.

 

[ch1ch2]

It sounds like you have very high water pressure. Are you on a municipal water system? Do you know what your actual water pressure is? We once lived where we were on town water, and the pressure was quite high, resulting in banging pipes. The water hammer arresters help, but I ended up adding an adjustable pressure reducing valve near where the water line came into the building. I was then able to turn the pressure down to an acceptable level.

As I recall 60psi is the preferred pressure for most homes. More if you have outdoor irrigation. Never above 90psi.

 

[BoylermanCT]

I was told 60 is the maximum. I have well water and the pressure switch is a 30/50 switch. They also sell 20/40 and 40/60 versions.

 

[ning]

I got terrible water hammer also when I replaced the washing machine. I think that modern ones have much more rapid acting valves which contributes to the suddenness of the water stop, and they also turn the water on and off repeatedly.

My situation was mostly remedied by a similar arrester device placed at the washer's valves. I think mine have springs in them? Anyways, my problem isn't all gone, but it's minor enough not to care too much any more.

 

[ArlyA]

This is the solution. Water hammer arrestors are fix for many modern appliances.

I got terrible water hammer also when I replaced the washing machine. I think that modern ones have much more rapid acting valves which contributes to the suddenness of the water stop, and they also turn the water on and off repeatedly.

My situation was mostly remedied by a similar arrester device placed at the washer's valves. I think mine have springs in them? Anyways, my problem isn't all gone, but it's minor enough not to care too much any more.

 

[CMV]

Mine isn't that little sound at the machine when the valves close. I get that but think it's pretty normal. This is a constant ca-chunk ca-chunk ca-chunk sound at the upstairs showers pipes while washing machine is running downstairs.

I just ran to home depot and looked for larger arrestors since I know Lowes only has the kind I bought. HD had the same thing but different brand so I bought 4. Figured I try just adding more. One leaked like crazy no matter what so I have 3 on the cold side, 2 on the hot side.

That really quieted it down and now I get a little rattle in the upstairs pipes at shower but only when the valves close and not nearly as loud. Tolerable just about.

But now there is a buzzing sound as it's washing........ This might turn into a tractor thread as my frustration level keeps rising.....the NX could smash this stupid washing machine up pretty well I think

On city water with real high water pressure. No idea what it is or how to measure it, but we have great water pressure here compared to my last 2 houses.

I'm off Monday so will try draining everything as described above to see if that helps.

 

[Xfaxman]

Way off topic - sorry - but figured you guys would know this & get me going in right direction....-----------------

In addition to that I tried partially closing the faucet valves to the washing machine going as far as to just let them trickle and take 20+ min just to fill. Also tried partially closing the main water valve basically reducing water pressure to whole house a little bit.

--------------------------------------------------

Partially closing any valve doesn't reduce pressure, it only reduces flow. As you found out with the slow filling washing machine.

 

[mapper]

When our house was built the plumber did not put in risers, when I questioned it, he told me the pressure tank made them unnecessary. He was wrong, we had a bad water hammer. The pump house and pressure tank are located about 600 feet from the house. My solution, which has worked very well, was to install a small (15 gallon) pressure tank under stairs in the garage.
Our line from the well to the house is about half 1.25 inch PVC and half 1 inch black poly, the PVC section replaced the original 1 inch 90# black poly that the original owners had installed, it had cracked, probably from the water hammer after we built our present home. Long story short, a water hammer can cause damage to your system that is not confined to your house where you hear it.

 

[RoyKing]

WATER HAMMER DEVICE CHEAP

Buy three pack of the gas filled racket balls, no the ones with holes. Put them in the freezer

Now buy some pvc pipe same size as racket balls, cap one end stuff the three frozen rocket balls in arrange so the incoming water heads at the balls T off outlet for washer. The balls will never water log.

 

[PILOON]

On the lighter side, water hammer serves to test your solder joints for poor soldering technique.
The bad 'cold joint' will blow open, LOL.

 

[Egon]

Close the washing Machine water inlets. If that stops the water hammer you got a place for arrestors.

If it does’nt check if your water tank is logged or if the well pump is constantly cycling.

The home built arrestors may result in stagnant water and do not meet code.