My son has a noisy ball valve in a toilet cistern it is a bottom entry valve. I am not keen to change the whole valve fitting as I would prefer not to break the connection to the mains water supply (my son lives 80 miles from me and is not keen on DIY so any problem after the event will be mine) are the valve fittings/diaphrams a standard thread/size? I cannot find a makers name on the fitting (it is a new build house so fittings are likely to be at the cheaper end of the market). I would like to buy a replacement and just fit the new internal valve leaving everything else intact.
One further point there is no overflow outlet so any leak could be a problem. Any advice would be appreciated also has anyone had experience of the electronic hard water treatment systems??