Pipe water Hammer? What is it?

[Roo]

Hi guys,
this is slightly left field we have just moved into a new house this week , the place has some serious pipe hammer like when you turn a tap on or off or flush the toilet its like depth charges going off in the walls so much so tonight it just dropped the bottom out of the hot water unit in the roof...... water everywhere.

What causes pipe hammer , how do you stop it and this made me think does it occur in engines? particularly when they use pumps in the cooling process???

Cheers,
Roo

[Phillip Hutchinson]

HEY YA ROO.Pipe hammer as you call it (water hammer) is what happens when you turn of the tap and the water in the pipe keeps on trying to keep going KINETIC ENERGY,I would imagine that you have good water pressure in your house.I would ring your plumber and tell him to get his buns down there and fix it.happy plumbing

[Roo]

Hey Phillip,
the pressure is not what id call outstanding. But seriously how does it actually hammer? I can understand something like air that is compressable doing it but since water isnt how and why does it make all the noise??

thanks,
Roo

[CWC]

Somewhere you probably have a long straight run of pipe that isn't tied down real well and as mentioned before the waters kinetic energy builds up then slams into things when you try to stop the motion. They make expansion chambers that look like little one gallon pressure tanks. These go in line and act as a shock absorber to keep that from happening.

[MoRo]

Until the plumber gets there, try closing your water taps s-s-sl-l-l-lo-o-o-ow-w-w-w-l-l-l-y-y-y and see if that makes a difference. If it does, then, if possible, check your pipes to see if some of the above-mentioned longer runs can be tied down somehow. Might save ya a service call.
My first thought was that some air got trapped in the lines somewhere, but that should have blown out a tap by now.
Good luck, Roo.
~B~

[Michael Studier]

What you see in the midwest is when the pipe comes up to the faucet, instead of an elbow to bring it out of the wall they use a tee and a short (18") capped vertical inside the wall that traps some air and the air is a cushion for the hammer.

Sometimes the air gets absorbed and the hammer comes back, then you turn off the supply coming into the house and open the faucets to drain the pipes and when you turn the supply back on the cushion is back.

[Rick Strobel]

Roo..we can buy those Hydrostatic shock absorbers here in the states..almost anywhere..easy enough to build also as previously mentioned.
Try turning off the main shutoff valve where the supply water comes into the house. Then turn on every faucet in the house and the outside ones also. KIll the water heater and drain it also. The lower the faucet (in elevation) the better drain you'll get. Let set for a couple hours and then go back to normal.

I'll try to find a Hydrostatic shock absorber on the net.

and yes it can bust pipes

RickinMt.

[Rick Strobel]

Roo..do a google for "Water Hammer in homes" w/0 the quotes. Here's what's happening:

Bangs, hums and singing from plumbing pipes: The plumbing pipes and fixtures in your house can make a variety of noises. A banging noise when faucets or other appliances are turned off is typically caused by water hammer. Water hammer results from pipes being jarred due to a sudden stop in water flow.

Most of the time water hammer can be remedied by installing a water hammer suppressor. The most common suppressor is a vertical section of pipe 10 to 12 inches long installed at the fixture. The air in this pipe acts like a cushion, absorbing the shock. Sometimes, however, the air gets absorbed in the water, allowing the water hammer to return. To avoid this, install a manufactured arrestor that uses a pressurized bladder to absorb the shock.

I HAVE ONE WITH THE PRESSURIZED BLADDER
RICK

[Elden DuRand]

Originally Posted by Rick Strobel

.........and yes it can bust pipes RickinMt.

Reminds me of when I was in charge of keeping the pipes in an old, vacant 5-story building from freezing one winter.

The heating plant was a really old low-pressure (10 PSI) boiler feeding a 1907 single-pipe steam heat system with old cast-iron radiators all over the place. A single-pipe system is where there is no return line.......the condensed steam returns to the boiler by gravity, going against the flow of steam.

When one of these systems gets water logged, it can get exciting, especially when a lot of the pipe was new in 1907.

Since the natural gas fired boiler was very old and the controls were doubtful at best, I had installed a 35 degree temperature switch on the 5th floor and an alarm company monitored it.

At about 3:00 one morning on the coldest day of the winter (about zero), I got a call from the alarm company saying that they had a low-temp condition reported.

Got dressed, drove 25 miles to the building, let myself in and found that the automatic boiler water feed had malfunctioned, allowing the boiler to over-fill to the point that the pressure switch opened, faking the burner into thinking that steam was up.

It was COOOOOLD in there! First thing was to give the feedwater float valve a whack with an especially designed brick to make it turn off. Then I jump started the burner. Next thing was to drain a LOT of excess water from the boiler. Then I walked the building searching for burst pipes.

About the time I finished my walkthrough, I knew that steam was starting to flow because the building sounded like a locomotive factory. I could hear slugs of water swish through a long section of pipe, then a BANG as it hit an elbow.

I ran down to the basement and turned off the burner and closed the steam supply pipe. All this did was allow a lot of water to drain down to the valve. As soon as I cracked the valve.........the hammering started right up again.

Finally, after I let the pressure drop real low, I was able to let the steam force water from some of the low spots in the pipe. I also had to drain a lot more water from the boiler.

The good thing was that nothing broke. The bad thing was that I had to stand around for hours waiting for some of the pipe to thaw so, if a leak developed, I could deal with it. I was in a bad mood for the rest of the day.

Well - that's my story and I'm a-stickin' to it!

Take care - Elden

P.S.: I dunno what this has got to do with the thread but, since I've spent the time to type it up, I'll just let it go out. Hey - if you can catch me, string me up!

[21avery]

you probly have a pin hole in the pipe just above the deep well pump , just went threw this .

[Kevin O. Pulver]

Elden,
You sound like you might enjoy my other favorite web-site. "www.heatinghelp.com" They have lots of old steam and hot water articles in the library, and a nice chat room too. Kevin
As far as water hammer goes, lots of times it's the automatic valves in dishwashers, washing machines etc... that make it show up because they slam on and off so fast. The fix COULD be as simple as clamping a pipe better (not always possible) OR putting in the water hammer arrestors listed above. Sioux Chief is one manufacturer, and they make some that screw on right between your washing machine box and washing machine hoses. They might be the easy fix for you! Anyone who tinkers with engines could install them him (or her)-self with a small pair of channellocks or visegrip. You can find them at any wholesaler or search the internet. Merry Christmas!
Kevin

[Luke]

Hi Roo

I am in Australia and in the Building game. You can buy inline hammer arresters which are a small version of the energy or shock absorber on a water pump. These are quite small and can be fitted at points where the hammer is at its worst. As mentioned in an earlier post, the water pressure and poorly fixed pipes are to blame.

Merry Christmas to all!
Luke

[BobRR]

Roo you should have air chambers or arrestors close to any fast closing valves. under kitchen sink on hot water line if you have a dishwasher, one on hot and cold for the washing machine.Toilets can cause it too. ballcocks or a leaking flapper can set up a hammer usually replacing the ballcock & flapper will cure that.Are you on a well or city water? How old is the house? I dont know the codes for there but here code has called for them since at least the 50's. If you think your house should have had them installed alot of times they will be in the wall.Draining the house down to the lowest point will let air in the system and recharge them.If on a well make sure there is a air charge in the holding tank. Hope this helps. If not let me know. BobRR

[Phillip Hutchinson]

G'DAY ALL.
I related this story to Roo on the chat room last night and he told me to put it on here so here it is.Some years ago i used to work for an irrigation engineering co,anyway one cold winters day the boss comes out and say's to me can you go have a look as to why Mr Marrows has no water coming out of his irrigation system.So off i go to find the problem,come over the embankment to where the pump should be,NO PUMP! just a broken 12" fibrolite pipe snapped off clean as a whistle and 2 marks where the pump beareres used to be.The give away was a trace of oil slick on the water.i went back to work informing the boss,his reply BS.So he come for a look and sure enough the whole 6 cylinder diesel engine 12" pump and 200 gals of fuel where in 30 feet of water,so we called in a diver to hook up the slings to lift it out.What happened you ask,well what happened was that the pump was going at full steam pushing a 12"column of water up 1/2 a kilometer of pipe to a head of around 20 feet,and the watch dog shut the engine off,so all the water travelling at 15 kph suddenly reversed direction and flowed back into the river until the footvalve slammed shut,with all that kinetic energy stored up all that was stopping it was the pump,so hence the water hammer flicked the whole lot into the drink,the pipe had a cubic meter of concrete on it to no avail.

[BWegher]

Get a licensed plumber to inspect everything. Ask him if the previous owner should be held responsible for whatever was wrong, then send them the bill.

[Steve A]

Water hammer also can have a practical use, it is the same thing that makes a water ram function. Water that is flowing through a pipe that is suddenly stopped causes a pressure spike making the sound and shock, if you divert this spike into a pressure tank through a check valve water can be pumped up hill using only the power of the flowing water. Search the web for water rams to find more. steve

[tcalhoun]

i have done alot of hydraulic work and we use a thing called a bladder accumulator that can be installed in line to take out some of the shock and jerk from the lines i am sure they are called something different for plumbing use and the ones i used you put nitrogen on top side of the bladder at about half the pressure of the hyd system if you were using it for shock absorbing or you could use it like a storage tank and it would help smooth out the volume or flow. I think i have seen some that have a bladder and u can put air in the top side of the bladder. this would work good.

[Jim Conte]

Roos and Yanks, and any other variety of terrestial out there...
100 % in agreement with discussions of hydraulic shock absorbers / accumulators. The yarn about water hammer knocking the diesel pump down to Davy Jones still has me giggling...

Just wanted to add my 2 cents worth, possibly the water pressure is too high to start with. I once had the task of installing a water softener in a home at the base of a hill that had the town water tank on top. The water pressure in that house was 140 PSI ! The softener tank was rated at 100 psi max, so I explained to Mr. and Mrs. homowner how we needed to add a pressure regulating valve upstream. We set the regulator for 40 psi. When the water pressure was turned on- at 40 instead of 140, the missus commented that flushing the water closet no longer sounded like a jet plane taking off down the hallway. This might help ! Good Luck !

p.s. Is it true that the toilets swirl backwards down there in Roo Land ?

[Ray Freeman]

If you put in a hammer arrester make sure its not made of anything prone to corrosion. They rust out on at the most inconvenience times. Ever tried to buy copper fittings on Christmas day?

[Sky]

Why would anyone stick a hammer in the water pipes .....
well guess i'll go on and comment on sumthin else now.