Set Square wrote in message
...

Wonderful - but who's going to understand it when you're not around?


I'll leave my inheritors the Google Groups link to this thread

Incidentally, what's the 'top-up' tank in the primary circuit for -
bearing
in mind that it's a pressurised system with pressure vessel and filling
loop?

You're right - I don't really need the tank. I had half a mind to use it to
monitor the volume of water that had escaped from the system so that I could
assess whether there were any leaks.