Water hammer that isn't?

[supton]

Not sure what term to search for. Over the last few months our toilet has developed a hum just after it stops filling. Not a hammer, but a hum. Which I'm guessing is still related to water hammer?

I'm not sure what has changed, as nothing in the plumbing has changed. Maybe I should change the fill valve on the toilet? I'm not sure if its been replaced in 12+ years.

 

[mk378]

As long as the fill valve is still turning off eventually, that kind of noise is harmless. Several hours after the last flush, check that the tank stopped filling before reaching the overflow tube.

 

[LeakySeals]

The only water hammer I'm aware of is a dry over-pumped well. When the well recovers enough to cover the pump, the pump sends water into the system, pressurizing so fast your pipes "bang" the joists. Try cleaning the bowl and the seal/flap that opens to flush.

 

[Kira]

Air in the water? Well? municipal water?

 

[Pop_Rivit]

The fill valve can develop a hum after filling, especially if it's and older, metal valve. It doesn't hurt anything, but if you want to fix it just replace the fill valve.

When it starts making the noise, just live the top of the tank off and see what's vibrating and making the humming noise.

 

[Danno]

Seems to be a lazy valve where it takes a few seconds to fully close, causing the noise. Probably wear related or dirt in the valve. Changing it would probably fix it, but with toilets, once you touch something, seems like something else goes wrong, flapper, seals, so I would leave it unless it gets really annoying or starts to not fully shut off and then leaks continuously.

 

[supton]

I have a well. No air in the lines, that I know of.

Thanks, I'll see about getting a new fill valve. Not doing it all the time, but that part should be cheap enough to replace.

 

[Virtus_Probi]

We developed water hammer over time in our first house (city water) that was only an issue with the downstairs toilet. In that house, it was dirt simple to drain the system through the utility sink in the basement and that took care of it...just kept all the taps on while allowing the pipes to refill until everything ran freely and the hammer was gone.
If it's easy to drain your system, why not try it...if it's a pain, maybe try to fill valve first in case it's not water hammer.

 

[doitmyself]

There are still 2 U.S. manufacturers of fill valves: Korky in Wisconsin and Cesco in Colorado. Korky's run about $12-$15 dollars and I would recommend the silver top Universal model that has adjustable bowl refill (order the pro model if high pressure is a problem). The Cesco is brass and costs around $40 or more.

 

[ARCOgraphite]

If you have a drilled well, make sure your expansion/holding tank has the correct air bladder preload ( must check empty - shut off well and run water till pressure reads -0- (zero) also make sure your high limit is shutting off at the setpoint (50-60psi)

 

[64bawagon]

Its not water hammer, like others have said, its likely the valve being slow to close

 

[SHOZ]

Originally Posted By: ARCOgraphite
If you have a drilled well, make sure your expansion/holding tank has the correct air bladder preload ( must check empty - shut off well and run water till pressure reads -0- (zero) also make sure your high limit is shutting off at the setpoint (50-60psi)
And then check it every year. My bladder tank is under the house. I took out the valve stem out of the schrader valve on the tank and ran a hose up to the garage area where I have a schrader valve on the end to check and add air from the ground floor.