Heating Help

Fightin' the hammer... (OT)

So let me start out by saying I'm a heating man, I know just enough about domestic plumbing to be dangerous. ...but, anyways...I see to have a water hammer problem at my home. When the dishwasher solenoid valve closes or a faucet turns off, you can sometimes here the pipes knock around in the walls and sometimes the flush valve in downstairs bath runs for a second. I feel like I need to put a hammer arrester in, but it seems to me like those are typically put right at fixture, where my problem is more system wide. There is no backflow device on the house and therefore no expansion tank. The city water pressure averages about 90psi! ...Anyone have any thoughts on the placement of a water hammer arrester.
Thanks!

drop the hammer

Although you probably like having that kinda pressure for your personal use, you're asking a lot from your fixtures and appliances to close quietly against that kind of pressure.  A domestic water pressure tank installed somewhere near the meter may help but your better off installing a pressure reducing valve in line right after the meter.  I usually put them in with pressure gauges on either side and dial it in to about 60 psi

Yep,

you're right, the hih pressure has it's benefits. The run outs for all the fixtures are exposed in the basment below. I realized might be a little excessive, but do you think it would be effectiv to put something like a shock-trol on each of those runouts?

Watter hammer

Have you always had the banging or is it a recent development?  My home has 100 psi water pressure. I have installed a regulator, but not due to hammering issues. (100+ psi can wreck a garden hose)

I'd look at the toilet that runs, faulty ballcocks can cause hammering. Older two handle sink faucets with loose washers will also cause problems.

Jim

reducer

Hello:  I'll agree with Jimmy that a reducer will help.  I'd put it in the line going to the house, leaving any garden bibbs at high pressure.  An expansion tank downstream of the reducer will keep the pressure at set point rather than having it go up and down as the water heater works.  The reducer will slow water flow, reducing hammer.  Another possibility (second choice) is to put arrestors at every fast closing valve.

Yours,  Larry

90 psig too much

 the correct way is to  install reducing valve and expansion tank.

What,

would you suggest is an ok pressure, on the high side?

I'd set it

at 50 to 60 psi, max.  And a nice bladder type expansion tank should do wonders for you -- doesn't have to be all that big.

expansion tank

remember, the expansion tank is for potable water.