New hot-water cylinder after three years??

[Best]

I have seen motorised valves intermittently working and also preventing the hot water to be fully heated.

 

[Moonraker]

Um ah. It appears that the second plumber didn't tighten something on the "hot tank" (perhaps he checked the immersion element?) resulting a leak down a wall. The third (Polish) plumber:

"came to similar conclusion as others. There must be something inside the cylinder that might fell off and got stuck somewhere or it’s the lime scale. He advised to contact [housing-site] developer ( so we did - but he said that’s not his business and we need to contact the cylinder manufacturer ). He sees two solutions: To take the cylinder out and clean it then install the water softener or buy the new one with new water softener."

Of course contacting the manufacturer is a waste of time - it will obviously (and reasonably) point to the installer - and I see from other threads that blockages in pipes can cause problems to a cylinder's efficiency.

I think we've taken this far as we can, and I'm grateful for your input.

Now as it happens, another Polish friend has just been gifted a house in East Kent. A new boiler was installed three years ago and for most of that time the house has not been lived in. Now Evey has been quoted £500 for repairs to the boiler, which broke down shortly after she moved in ...

Seriously, no need to reply; I'm just noting the minor coincidence.