So SWMBO has won a pressure cooker then!!
I have taken pics of the re-assembly of one of my RIMS heaters.
It is quite a bodge, so I hope that nobody thinks that this is the way Garysmiff did his own!
You get the wrapped compression reducer looking like this:
It consists of these bits:
The usual assembly on a bit of 15mm pipe is, I believe:
I mounted the seperate bits in a tank connector to hold while drilling out to 16mm:
I discarded the olive and added two o-rings (15mm OD 2.5mm section); this shows a tank connector coz I didn't have a spare T-piece:
I wound some ptfe tape round the second o-ring (about 5-6 times):
A smear of clear silicon sealant for luck (and to make it all slide together) and the finished assembly:
All else should be clear from Garysmiff's original post.