Expansion Tank for Home Water Supply

John Roberts

David, The first thing for you to check is your incoming water pressure from the street, if your incoming pressure exceeds 65-70 PSI (I have seen some well over 100 PSI) I would recommend a whole house pressure reducing valve such as a Watts U-5B and knocking down the incoming pressure to a manageable level of 50-60 PSI. Be sure your plumber installs a proper wye strainer upstream of the valve, and bypasses the valve so in case of a malfunction you will not lose water service. 50-60 PSI is enough pressure to insure good performance from your fixtures and will help solve water hammer problems, and reduce wear and tear on the piping.
JR

Dave_23

Expansion Tank for Home Water Supply

Folks,
I know this is a bit off topic, however I have a water hammer problem when cold or hot water in my home is turned off abruptly. For example, when the washing machine shuts off, the shockwave really rattles our pipes. The original air cavities installed at the fixtures clearly are insufficient. Compounding this is that our house was originally equipped with Sloan valve toilets, therefore we have a large diamater tap of the water main and subsequently lots of pressure. What do you folks do to eliminate household water hammer?

Brad White_9

Arresting Water Hammer?

Water Hammer Arrestors... of course!

Expansion tanks have some effect but are not the recommended product. Watts among others makes them. Forget the old-fashioned up-turned air tube- they eventually fill with water. You need a spring and pneumatic unit or several made for the purpose.

To get an idea of hydraulic force, I had a plumbing systems design instructor tell me a story. A fellow was working on a waterworks and closed an open gate valve (lever type drop gate) too quickly. About a quarter mile of 8" water main jumped out of the ground according to the tale...

Point being, you cannot have too much shock absorbtion.

Dave_23

Water hammer arrestors

Brad,
I'm not familiar with these? Where would they typically be installed in a residential application? Can you describe one or suggest a reliable make and model?

Plumdog_2

watts and sioux chief

You can install hammer arrestors between your washer valves and your washer hoses. I've seen them at Home Depot,in fact.