7 April 2012: Well the plumbing of Saturday has been indoors, the system is now topped up with new liquid, and I hope it will all work on Sunday when I turn it on in daylight. I don't know why I have been so reluctant to use compression fittings in the past. For years, I seem to have been set on soldering everything. Maybe, I was doing it because it is cheaper.
It is so much of a nuisance when you need to do a repair, as you cannot heat out an old soldered joint if there is liquid inside, and also, glycol has a peculiar ability to find its way out of the slightest fault with a soldered joint. I am using PTFE tape for most of my new joints instead of putty, its clean and dry. The picture above is a sort of 'Still Life' for plumbing junkies.
I now have a 12 litre expansion bottle in the circuit immediately connected to the Surya Sunbox panels, even if the valves are closed. There is also a pressure gauge to keep an eye out for leaks. The bottle is held up with wires at the moment, but if the plumbing works, I shall insulate all, and will build a proper supporting bracket from spare aluminium. I'm not sure how much of the air I should let out of the balloon inside, but I will read the pressure gauge and either let more out or pump more in, depending on performance.