# Potential for Water Hammer



## fish1349 (Mar 16, 2014)

Hello all, first post for me here, so let me know if this is the wrong forum to post this on.

I am working service on an old home and ran into a shut off valve halfway along a pipe. The owner, a handy man of sorts, said not to close it at all because it would cause a hammer. Although I disagreed with him about not closing it at all (would have done it slowly instead), the customer is always right! :thumbsup:

Has anyone here had an experience when closing a valve along a pipe has caused hammer? Even closing it quickly, would that cause a hammer?

Sorry for the novice question, but I am a novice plumber and do not wish to ask my boss (as he assumes I know everything about the trade)


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## Tommy plumber (Feb 19, 2010)

I assume nothing fish.


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## Leach713 (Nov 1, 2013)

fish1349 said:


> Hello all, first post for me here, so let me know if this is the wrong forum to post this on. I am working service on an old home and ran into a shut off valve halfway along a pipe. The owner, a handy man of sorts, said not to close it at all because it would cause a hammer. Although I disagreed with him about not closing it at all (would have done it slowly instead), the customer is always right! :thumbsup: Has anyone here had an experience when closing a valve along a pipe has caused hammer? Even closing it quickly, would that cause a hammer? Sorry for the novice question, but I am a novice plumber and do not wish to ask my boss (as he assumes I know everything about the trade)



First of where is your intro at?


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## fish1349 (Mar 16, 2014)

Leach713 said:


> First of where is your intro at?


Leach, what do you mean by intro?


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## Tommy plumber (Feb 19, 2010)

An intro is requested from all new members. In case you missed it, here is the link. http://www.plumbingzone.com/f3/.

The PZ is for Plumbing Professionals ( those engaged in the plumbing profession)

Post an intro and tell our members where you are from, yrs in the trade, and your area(s) of expertise in the plumbing field.

This info helps members who are waiting to welcome you to the best plumbing site there is.

We look forward to your valuable input.


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## Leach713 (Nov 1, 2013)

Your plumbing experience background; ect.


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## fish1349 (Mar 16, 2014)

Oops, missed it, thank you both for the information.


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## plumbing ninja (Jan 15, 2012)

Water hammer can be a beartch esp with things like solenoid valves. If handwheel valves are used its less likely water hammer will happen when u close it. It is a good habit on lever valves on liquid lines to slow close and open! On large lines 4in + you can see the line shudder violently. Water hammer is caused by air settling in the upper portion of the pipe and at high point of a closed system. You will always have air in your system as it naturally comes out of soln!


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## dannyoung85 (Oct 8, 2013)

I thought water hammer was caused by liquids being suddenly stopped inside pipes (via fast closing valves) and that energy having nowhere to go other than transferring throughout the piping system resulting in the hammering sound made by the pipes.


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## alberteh (Feb 26, 2012)

plumbing ninja: you have much to learn young grasshopper as dannyoung85 has schooled you.


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## wyrickmech (Mar 16, 2013)

dannyoung85 said:


> I thought water hammer was caused by liquids being suddenly stopped inside pipes (via fast closing valves) and that energy having nowhere to go other than transferring throughout the piping system resulting in the hammering sound made by the pipes.


 you are correct water hammer is the sudden stop of flow of a moving column of fluid. Sense the fluid cannot compress it becomes a solid force making a hammering effect for just a split second. The shock wave that is created travels in the opposite direction having the same effect at every turn in direction. That's why the closer to the source you can get the arrestor the more effective it is.


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## fish1349 (Mar 16, 2014)

Thanks for the explanations everyone. I thought I may have had a mix up, but dannyoung helped me realize my assumptions were correct.


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