Noisy cistern valve

[Thomas]

Hello

We've had a problem with banging mains water pipes recently which I traced back to a cistern valve that I recently replaced. The valve is a very compact bottom entry type with a float on a very short lever - I believe they are called Torbeck valves.

- see item with Code 32033

It seems like the valvle is on a hair-trigger and the slightest vibration can set off a short cycle of open/close giving rise to quite a loud water-hammer in the mains pipework. This can happen when a cold tap is turned on or (more disconcertingly) when someone sits on the loo - I think this causes a slight wave in the cistern water leading to a movement in the float.

Any suggestions? Is it a feature of this model of valve, a fault in this particular valve, or does the problem lie with the pipework or mains pressure?

Thanks for any advice Thomas

[DerbyBorn]

"Thomas" wrote in news:ZE2ss.471501$Bz2.264444 @fx11.am4:

resiliance and therefore some tolerance to slight fluctuations. Alternatively consider changing to a Fluidmaster Valve.

[harry]

These valve are pilot operated. ie the float controls water with a needle valve into a chamber with a diaphragm that actually does the business. The banging is caused by a wave/ripple on the surface of the tank water that just happens to be the frequency that corresponds to the valve opening and closing.

So it's because of the size of the tank and water flow. Try throttling the water flow. The isolating valve will need to be nearly closed to have any effect. If that doesn't work, try floating a plastic ball inside the tank to interfere with the wave pattern on the surface of the water. Make sure it doesn't interfere with the float.

Try adjusting the float so there is less water in the tank.

Try fitting a condom or similar on the water valve outlet. (Reduces splashing/wave effects.)

[harry]

Obviously, cut the end off the condom!

[Nthkentman]

Obviously, cut the end off the condom!

But that'll make the cistern pregnant won't it?

[Thomas]

Thanks for the helpful suggestions.

I played around with the float level and reassembled. So far so good :-)

Thanks again Thomas

[The Medway Handyman]

Torbeks are supposed to reduce water hammer :-)