Thread: Loud whining noise since ball valve replaced - why?

A similar query was posed 3 years ago here, but it doesn't quite fit my circumstances and I’ve been unable to find any other information......please can anyone help a capable blonde with the following dilemma?
After several months of an overflow pipe leaking I traced it to the header tank to our hot water cylinder. The ball valve was not closing off the incoming water properly. I purchased a new ball valve, and fitted it in place of the old one – ensuring that the assembly was level and square to the tank and water. Apart from a slight weep on the main inlet pipe, which I eventually sorted with some ptfe tape and a little more tightening, all was fine.....overflow running leak fixed.
Two days later I noticed that once the hot water had been running a while there was what can only be described as a ‘whining’ noise from cylinder/tank area which continued for about a half to a full minute after the hot tap had been turned off.
Three weeks later and this whining is now extremely loud and as above starts a while after the hot tap has been running and stops about a minute after it has been turned off.
I am sure this must be a very simple mechanical problem. Sadly I’m not in a position to call out a plumber so I would very much like to resolve it myself.

Please can anyone reading this spare the time to advise me what I should be doing/checking? The solution to the previous query 3 yrs ago was to install a new ball valve – but for me the noise only began after the valve had been changed.
Thanking you in anticipation of a solution

A restriction in a pipe or valve can cause chaotic flow and that can emit a sound.

Ball valves are pretty simple, so I wouldn't expect that unless it's just opened slightly. I've also heard noises coming from a conventional washer-type valve where the washer was loose.

On your rising main stop tap try turning the pressure down just a little

This could be caused by the water flowing either side of the washer, which has deteriorated or was left out the simple solution is to change the washer or fit one if you have not already done so.

Change it for a 'silent' valve. It is unlikely that the existing one is fixable.