water hammer

ryan_2

have 2 twinned 30gallon hot water storage tanks,heated by boiler loop.problem is when using hot water from faucets,shower i get very loud water hammer, not when turning it off but while runing for the first 20-30 seconds.i installed a properly sized thermal exspansion tank and hammer arrestor on the domestic outlet of the storage tanks.also because of high city water press. i insatlled a press. regulator on the main set for 65psi. original press about 120psi.have not had any luck stopping the hammer.could use some expert advice. thanks

Bill_14

Water Hammer

Do you have an air shock at the fixture? Is your pipe supplying this fixture properly anchored or are your hangers installed correctly? Is there a valve in the line?

Bill Russell

Bob Gagnon plumbing and heating

loose washer

it's probably a loose washer in one of the shutoffs. bob

kevin

I agree w/ Bob.

It it a Symmons ? I have had problems w/ washers and hammering noise.

Big Ed

I agree with bob...

Sounds like a broken bib screw and a loose washer.............. But! But!........Remove the thermal expansion tank and make sure the tank's charge matches the incomming water pressure . Reminds me of this job years back , after a pile of service ticket's that was the solution to the problem. ......

Mark Eatherton1

Passing bad checks...

IF it has a circ return, and IF it has a swing check in a down flow position, I HAVE seen this scenario hammer. Water starts flowing in correct direction, and if the pump is on, it's OK. But as soon as the circ pump shuts off WHAMO. Water hammer. I've even seen it happen with the pump off.

Just when you think you've seen everything there is to see, ya find out you ain't seen squat...

Another question for you Ryan, does the water temperature or pressure change at the shower head when it hammers?

ME

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Canuck

I agree with all - but

see if your PRV isn't faulty as well. If you're using something smaller than a Watts U5B there may be too much 'droop' in the system.

Online Sheriff \"Murph\"

ryan what kind

of shower valve do you have?? maybe a bad cartridge!! do you have the arresters (sheriff get it?) at the fixture as suggested?? the expansion should be at the cold inlet, and set at a few pounds under "working presure" of the system, checks and the looos bib screws seem to be good places to look!!

Harry Lewis

You can't install a bladder expansion tank in any system without checking the charge pressue in the bladder. Typically they come from the factory with a 12 psi charge. If you are installing this on a system with 65 psi and then with the fact of the hot water expanding, my guess is the xt is water logged. It must be charged to the pressure setting on the prv coming into the building. Also if you have installed water hammer arrest. the must be installed per the manufacturers recomd. You can not just cut it into a main line via a tee with the arrestor installed in the branch. The shock will bypass the location an transfer the hammer to th piping.....
Good Luck

Bill_14

Hey Ryan

You got that problem solved and fixed yet? What did you do? Let us know so we can all feel better that we tried to help ya.

Bill Russell