Water Hammer Arrestor and cold winter water...

Zipper13

I have added one of these to both my hot and cold water supply to my washing machine. I figured the "commercial" grade would last longer and it wasn't much more in price.

https://www.supplyhouse.com/Sioux-Chief-653-B-Hydra-Rester-Commercial-Water-Hammer-Arrester-3-4-MIP-Thread

I've had the hot arrestor there for about a year and cold is a couple moths old.

Both solved the water hammer problem instantly!

...but now the hammer is back in the cold supply - but NOT for the initial fill up of the machine, only for the rinse and the intermittent top-offs (its a high efficiency model).

I'm wondering if 1) I got a bad one that failed prematurely or 2) this is temperature related - the cold water coming in from the street here in New England is too cold for proper function of the internals?

anyone else encountered this? any solutions? the cold fill tees off like 3 feet from the meter so it hammers hard when the fill valve shuts!

Intplm.

Hello @Zipper13
The one on the cold water with that type of washing machine might be bad and lost its air charge? Or it is too small. It doesn't have anything to do with the cold temperature of the water.
I would return the one that is allowing for the water hammer and replace it. You will need to look and see if you have any other plumbing devices that are causing water hammer along with the washing machine.
A toilet, an auto-feed valve, a check valve, etc. can also cause water hammer.

Jamie Hall

Also, while you're at it, check your water pressure. Street pressures are sometimes pretty high...

Zipper13

Thanks all. So far the only other place with hammer was the toilet fill and I added a smaller one there with great results.

Since you say the cool water temp shouldn't matter, I'm going to swap the arrestors on the hot and cold and see if the problem shifts with it to confirm that it's failed (I didn't want to bother right away if water temp was a known issue, but it sounds like its not!)

I'll check the pressure too when I swap them - cant hurt!

mattmia2

Depending on the source and where the water is stored municipal water in winter can be close to 32 degrees. I always just use a capped piece of 12" to 18" pipe.

The other thing that might be happening is if it gets cold enough the charge in the arrestor might lose its bpressure bcaus of...i can never remember if it is charles's or boyle's law.

Zipper13

mattmia2 said:

Depending on the source and where the water is stored municipal water in winter can be close to 32 degrees. I always just use a capped piece of 12" to 18" pipe.

The other thing that might be happening is if it gets cold enough the charge in the arrestor might lose its bpressure bcaus of...i can never remember if it is charles's or boyle's law.

Oh ok..so the air might be getting denser in cold? I hadn't even thought of that when I asked if it was cold-related. I thought maybe the housing might have shrunk gotten the moving parts jammed up. I wasn't sure if it was air in there or a spring on watertight plunger.

mattmia2

I"m not entirely sure, I think there might be both, but there would have to be gas on the other side of the plunger regardless of if there is a spring as well and if that gas gets cold enough it might pull a partial vacuum and compress the spring.

Zipper13

@Youngplumber The whole idea of the air filled capped pipe chamber seems useless to me as overtime the gas ( air) will dissolve into the water and then the air chamber juts becomes a water-filled stub, no?

mattmia2

Water has air dissolved in it. i have little doubt that on the hot water side that air will come out of solution when it is heated and collect in the air chamber. How likely it is to come out of solution in the cold water side i'm not so sure.

jumper

Wonder how high rise luxury buildings deal with the issue?

Zipper13

jumper said:

Wonder how high rise luxury buildings deal with the issue?

I suspect booster pumps and roof tanks help maintain "normal" pressure

Intplm.

Zipper13 said:

@Youngplumber The whole idea of the air filled capped pipe chamber seems useless to me as overtime the gas ( air) will dissolve into the water and then the air chamber juts becomes a water-filled stub, no?

I remember years ago reading an article about water hammer, and water hammer arrestors in Plumbing & Mechanical Magazine. ( c. 1990 )
The article said something about selling snake oil and the water hammer air-filled dead-ended pipe assembly. ?
In short, this dead-ended pipe assembly that was thought to prevent water hammer was far fetched and didn't work. It was found that the homemade air space would, over time, be absorbed by the water rendering the assembly useless. And it didn't matter whether the water is hot or cold.
Since I read this article, I haven't installed any dead-ended pipe to act as an arrestor.

jumper

Gas is much more compressible than liquid. It's not that bad an idea to have a whole building shock absorber. How often do you suppose you have to re-pressurize the air space?

hot_rod

 maybe install a pressure gauge with an indicator needle, see if you are getting pressure spikes. Is there an expansion tank on the DHW, a backflow preventer?

Zipper13

no expansion tank and no backflow preventer that's obvious to a Joe Schmo like like me, though the meter itself appears to be marked as unidirectional. At any rate, the hot supply is no longer hammering on my washing machine since adding the arrestor a while back, it's the recently added arrestor on the cold supply to the washing machine that seems to have crapped out. which made me suspect something to do with temp...I'll be swapping each of them this weekend to see if it's just failed or if it may be related to temp.

hot_rod

Sounds like one failed, they are rated to 350 psi It is possible if you have high pressure and the meter yoke has a backflow device, a fast  closing valve can create a very high pressure spike. A indicator gauge with second needle will record that information. If a 2nd one fails I’d look for a cause

deyrup

They fail all the time we are on our 4th set, and they also have a tendency to leak. They usually fail after about a year, but can fail sooner. We are trying to get the plumber to install a pressure reducing valve on the main, but it is taking awhile. Our water pressure is around 90 psi.

Larry Weingarten

Hi @deyrup , Once you have a reducer in place, set to fifty or sixty pounds, you may no longer need the hammer arrestors as velocity in the lines will be so much slower. That approach has worked nicely for me.

Yours, Larry

Zipper13

This may be a really dumb question, but here goes. Both the hot and cold supplies are flexible braided hose that connect to the rest of the distribution piping at threaded gate valves. Can I just partially close the valves to solve the hammer by reducing the flow rate?

Larry Weingarten

Smart question!! It could work, so try it and let us know how the experiment worked out. I know gates should be fully open or closed, and a globe valve should be used for throttling, but still, it would be a telling test.

Yours, Larry

JUGHNE

Repeat story: I put air chambers at the washer setup in our old house. After a few years I could hear the icemaker valve snap with water hammer. Water main off and drain down at washer and then water on. The hammer stopped. This was on a 30-40 PSI city supply with no check valves or backflow devices.
So the air chambers worked, just had to recharge every few years.

New house with same pressure has expansion tank on cold supply to water heater. I think the ice maker is connected to hot water, I have never heard it operate.