Banging water pipes

[muncybob]

For some reason lately the cold water pipes are making a banging sound when the water shuts off to the toilet after filling from a flush and also when the washing machine cuts off supply to the tub. I seem to recall a fix which did not involve removing wall panels to brace pipes on a TV show but don't remember what it was?

 

[Buzz Saw]

Water hammer arrestor. I think that is what you want. Not sure if you can do a whole house or for each branch/fixture.

 

[Buzz Saw]

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[peakbagger]

Are you on well or city water? If it didnt do it before something changed. If its a well, look to see if the outlet pressure has changed, it is city water check the pressure. Some meters have pressure reducing valves that can fail or the city may have made modifications to the water system. All you need is around 30 psi anything more and its waste.

 

[semipro]

Addressing any issues with abnormally high pressure or adding a hammer arrestor at each offending appliance will probably be easier than trying to tack down and fix moving pipes.
You can also try closing the toilet valve down some so that the tank refills more slowly.
There are also larger arrestors that can be put on the main water pipe after it enters you house.

 

[DougA]

In this cold weather, be thankful the pipes are banging and not frozen.

 

[peakbagger]

By the way, the new constant pressure well pumps are reported to be bang free.

 

[iron]

suggest trying to drain your lines first before buying anything. shut off the water. open up everything (except maybe your hot water heater assuming it's at the end of the line). wait 'til everything flushes out. then, turn water supply back on and turn each item (sink, toilet, shower, etc) starting with the ones closest to the house shut off valve. worked for us.

 

[heat seeker]

suggest trying to drain your lines first before buying anything. shut off the water. open up everything (except maybe your hot water heater assuming it's at the end of the line). wait 'til everything flushes out. then, turn water supply back on and turn each item (sink, toilet, shower, etc) starting with the ones closest to the house shut off valve. worked for us.

I used to have to do this at my mother's place once a year or so. The arrestors apparently lost their air, and draining the lines let air back in. Also make sure any straps securing the pipes to joists, etc, haven't come loose.

 

[semipro]

The arrestors apparently lost their air, and draining the lines let air back in

Plumbers used to install top-capped vertical sections of pipe that filled with air that acted as arrestors.
Modern arrestors are sealed units much like a modern well pump tank.

 

[heat seeker]

Plumbers used to install top-capped vertical sections of pipe that filled with air that acted as arrestors.
Modern arrestors are sealed units much like a modern well pump tank.

Showing my age, I guess. But at least the old ones didn't need replacing.

 

[semipro]

Showing my age, I guess. But at least the old ones didn't need replacing.

Agreed. I still do it the low tech way when I can.

 

[muncybob]

Plumbers used to install top-capped vertical sections of pipe that filled with air that acted as arrestors.
Modern arrestors are sealed units much like a modern well pump tank.

I saw this on You Tube, I guess primarily in older houses and since our house is over 100 yrs old I gave it a try. It has helped but there is still a slight noise when running the washer. I have been able to open up the fill valve on the toiler a little more now though. Maybe I should do it again?

 

[billb3]

If you have municipal water rather than your own well the water pressure might be just a tad higher than in the Summer, or it may just be higher.
I've made my own hammer arrestors from 3/4 inch copper pipe because valves in a new washer really snapped shut quick.

 

[gzecc]

I would start with finding out what the actual pressure is. Buy a gauge at HD. Screw it onto your outside spigot.

 

[jharkin]

Are you on well or city water? If it didnt do it before something changed. If its a well, look to see if the outlet pressure has changed, it is city water check the pressure. Some meters have pressure reducing valves that can fail or the city may have made modifications to the water system. All you need is around 30 psi anything more and its waste.

I would start with finding out what the actual pressure is. Buy a gauge at HD. Screw it onto your outside spigot.

+1 Its not at all unusual to find the city water pressure much higher than its supposed to be. Our water comes in off the street at over 80psi. Anything over 50 voids the water heater warranty, etc I was told. We had a regulator put in the first year we live here to bring it down to 45 or so.

Fixing that alone may not stop the hammering however if you have valves that snap shut very fast and pipes that are not well secured. get the pressure under control first and if the noise is still present put in arrestors. I would be carefull trying to strap down every pipe to deal with it as they need to be able to move as they expand/contract.

 

[muncybob]

We are on a well, pressure is usually around 35 lbs. The only time it's happening now is with the washer although it is not as bad a before. So, how would I make/install my own arrestor for it?

 

[peakbagger]

On a horizontal run of pipe, cut in a tee with the branch facing upwards, install an increaser on the branch and install a vertical length of pipe with cap on top. There will be air bubble trapped in the pipe when you turn the water back on. It works although eventually the air bubble fills up with water. Alternatively pick up an a small expansion tank sold for hot water systems. It has a bladder in it so you never lose the air bubble.