water hammer

luvstac · #1 01/30/05, 12:14 PM

Can an air pressure regulator switch going bad cause water hammer?
Everything seems to be fine...air tank is full, pressure cut-in and out around 25 and 50 p.s.i. Pump seems to cycle fine and no water leak(fixed that last year) Other than the water hammer everything seems fine. The water hammer occurs when water is running and cycleing and cut-out at 50 p.s.i. Does NOT occur when you turn water off. Thanks for any input.

Alice In TX/MO · #2 01/30/05, 12:28 PM

Don't you have to turn off the water, drain lines, let air cushion in house re-air, then do it all in reverse?

Cosmic · #3 01/30/05, 12:33 PM

Did it always do this or just start?

Do you have any form of water hammer arresters installed? Maybe they have lost their air charge?? Or have failed if they are mechanical or bladder in nature.

See this for the general idea.

http://www.naturalhandyman.com/iip/i...infwatham.shtm

Just for chuckles this is misnamed. It is really a form of hydraulic shock only. True water hammer phenomenon involves pressure drops and water flashing to vapor / steam in an uncontrolled manner.

In your case, want to be focusing on what is quick acting to cause the hydraulic shock and what may be missing / failed / or malfunctioning that used to absorb it.

EricG · #4 01/31/05, 01:37 AM

Looking forward to hearing the suggestions. We seem to get hammer every time our well pump shuts off which it does a lot when the laundry is running etc..

Eric

Cosmic · #5 01/31/05, 01:59 AM

Doesn't sound right if related to a pump. Usually is a quick acting valve, like in a dishwasher or clothes washer. Solenoid valves that snap shut quickly, either full open or full closed. Did you check around for the arrestors in the plumbing. Just trace the copper water lines. Usually in the basement, can be under sinks, even look under the dishwasher.

Can be check valve slam. If the pump is the source and has a check valve in its discharge, this can snap shut as pressure decays. A check valve is like a little flapper in the line. Allows flow in only one direction. When flow attempts to reverse as maybe in this case when the pump shuts off, the check valve closes to prevent reversed flow. Usually is a small brass bump in the line, will have an arrow pointing in the flow direction it will allow. Can sometimes be built into the pump itself.

No matter the details, first you want to find if you have any shock / hammer arrestors in the system. Will usually just be little copper tubing stubs sticking out of the line with a cap on the top. Like as shown in that article I referenced.

Also can get up real personal with the system and attempt to determine exactly which component is causing the noise when it happens. Usually can isolate to a fairly small area. Just feeling the pipes gives a clue. Can have something similar to echos but after a while it should become apparent which component(s) generate the shock event.

Once you find the arrestors, identify the source of the shock wave then can attempt to drain the system and ensure the arrestors are once again filled with air.

agmantoo · #6 01/31/05, 12:34 PM

You can purchase a small 1 gallon size bladder tank and install it in the plumbing on the house near where the air hammering is the worst and it should correct the problem.

Cosmic · #7 01/31/05, 01:11 PM

Bladder tanks are way overkill.

Once you find the surge arrestors, (or if you don't have one in the proper place or can't find yours) if you don't like draining the entire system every so often to restore their air bubble can just modify the tubing.

Take out the upward pointing copper tubing stub. Install a same sized threaded ball valve on the tee where the stub was removed, rig the new tubing stub to screw into the ball valve. Using increased tubing size / length will help make it more effective. Fabricate a new stub for your application. Say if tubing is 1/2" make new stub 3/4". Or you can make it taller if it will fit. Most plumbers make them on the short side, lot just extend the supply lines up and dead head them above the elevation they turn to bring the water out in a laundry area. Sometimes behind walls. Can go nuts trying to find it.

In future if it loses the air bubble, shut the valve, unscrew the stub and drain it, reinstall and open valve. Using a ball valve instead of the normal globe style common home plumbing valves puts no restrictions in the line, hole opening in the valve is full line size. A gate style valve would also be acceptable.

They make surge suppressors that are filled systems for home plumbing. Some install in line instead of like the stub tubes. The el-cheapo fix is as I gave, lot of times can use junked rebuilt valves for the purpose.