On Monday, December 2, 2019 at 2:15:51 PM UTC, wrote:
Plan was to use 22mm blanking nuts on the solar in/out, and then chunk a compression nut and solve on a piece of pipe on every other fitting. Googling shows the existence of cylinder unions e.g https://www.bes.co.uk/22-mm-x-1in-fe...-end-feed-6794 - but I can't work out if these are simply a time saving device to make it easier to align everything for soldering, or if there is anything special about the connection.


Ignore that bit, I can see the difference now - 1" is not 22mm. But I'm assuming that in general a 22mm compression nut is actually a BSPP 3/4"?