Prolonged buzzing noise in rising main when tank nearly full

[speedycar53]

When the ball valve on the main water tank is close to shutting off there is a not very load but very annoying buzzing noise in the rising main pipework. This is not the usual water hammer, ripple effect or noisy flow of water in the pipework. It sounds more like a vibration emanating in the valve when it is in the almost but not quite closed state.

The noise continues for a good many minutes before the valve is finally fully closed and can be very annoying at night. The tank is large capacity - in fact two interconnected side by side (the house has 2 bathrooms and 2 ensuites all with power showers). I suspect it takes a while for the level change in the tank to be sufficient to cause the ball valve to shut off fully. When properly open, the flow is good but obviously the flow reduces as the valve is close to being shut prolonging the agony.

The problem has always existed from original installation some 5 years ago. Water is soft as we have a softener in the line.

Is this just a matter of a faulty valve or is there another explanation / fix?

If the valve, which brand / type of valve would be best to use in this situation?

 

[DeltaT2]

Certainly sounds(sorry no pun intended) like a slight water hammer, an 'air lift' fitted at the ballvalve connection may just do the trick. Or sometimes giving the ballvalve a file & a clean up will work wonders.
HTH

 

[spraggo]

It could also be due to the mains water pressure pipe work in the attic, connecting to the ball valve, not fixed or clipped sufficiently. Try steadying this pipe while the noise is present to prove a point.

 

[45yearsagasman]

Change the ball valve assy on the CWS tank if a clean doesn't work. Cheap as chips.

 

[speedycar53]

Change the ball valve assy on the CWS tank if a clean doesn't work. Cheap as chips.

I think the valve is being slow to close fully in which case replacement makes sense but with a better/top quality valve that has a rapid shut off. The buzz seems too high pitched to be any sort of water hammer as suggested in another earlier post.

Any suggestions for the best valve on the market?

 

[JTallsmith]

I had the same problem. I tried two new ball valves without curing it.
I eventually cured it by moving the float to the lowest position on the arm.

I guess it change the resonance frequency of the arm and it cured the noise problem completely.

I guess adding a weight to the arm would have the same effect.

John