I have finally put water into my central heating system. The bits done by a plumber didn't leak. The bits I did, despite (a) thinking I knew all about soldering and (b) being absolutely paranoid about cleaning the pipe, smearing it with flux etc, had about 4 leaks. Draining down the system to fix them is a real pain (and one of the ones I've fixed has just stared leaking AGAIN!).
Is there some secret method of guaranteeing a good joint? The ones I did in the open air (holding it up and playing with it) are OK - it is the ones in tight corners, assembled and then heated, that have gone wrong. When heated and pulled apart I can see that the joint was completely dry - just a ring of solder around the exposed end.
Should I use NON lead-free solder? Should one use a small, hot flame or a larger burner running gently? (I have a propane bottle & Sievert blow torch). Is one better off with solder-ring fittings (which I had) or plain ones, tinned by hand?
I'm now draining it down again and hope this will be the last time.
Thanks Roger