Whistling loft ball valve (after toilet refill)

[pwilki]

How can i stop the whistling noise after every toilet flush?
Yesterday I noticed the overflow was dripping - after investigation, i found the ball valve to be covered in scale and it could not shut the valve off fully. So i replaced the ball valve (allbeit with a slightly different style - instead of a portsmouth valve its now a diaphragm valve). Now every time the toilet is flushed, there is an annoying wjistling sound. I have tried adjusting the pressure of the the gate valve just before the ball valve. It doesn't sound like water hammer, and the washer should be OK (as the ball valve is new) any help???

 

[JohnD]

perhaps you have fitted a low-pressure valve to a high-pressure supply.

Get the instructions out of the bin and have a look.

 

[pwilki]

Thanks for your quick reply!
I bought the kit from B&Q, and it says "cold water header tank kit" on the front of it. Nothing is mentioned about pressure reccomendations - but i take it all header tanks are mains fed??

 

[JohnD]

yep.

 

[pwilki]

Any other ideas???

 

[TicklyT]

....... but i take it all header tanks are mains fed??

JohnD may know that, but I wonder if B&Q know that?

Ball valves are often supplied with both high and low pressure inserts.

I once had a valve that refused to behave quietly. A replacement was even noisier, but about two octaves lower. By playing 'mix and match' between the valve components I ended up with one quiet valve.

 

[pwilki]

There were no other 'inserts' in the pack...
How can i find alternative inserts that are the correct type...?

 

[JohnD]

are there any plastic bits screwed onto the float arm?

 

[pwilki]

No. Its just a metal arm with a 90degree bend at the float end, and the float is fixed to this via a retaining screw. The other end is secured to the valve body via a split pin, and the metal arm butts up against a plastic bung protruding from the inside of the valve body. The noise is loudest when the valve is almost closed, it sounds like a kettle is boiling! I thought a new valve would fix all my problems not cause another one!
Any help is greatly appreciated...