My solar hot water system was'nt holding pressure like it should, so I contact the firm that installed it. 'just cinch up the outflow joint at the collector' they said, 'the large temperature differences can cause this sometimes'. This was in all the appalling weather we had Feb/March/April, so I was'nt inclined to go cavorting around the roof, so I left it as was until things improved a bit. Well they have so this morning up I went, three sets of laders and some nifty ropework and there I was, taking off the insulation and shroud, and just as they said there was a little bleed from the compression joint. I carefully applied the spanner to the joint and cinched it up a bit. The bleed turned into a trickle, so I give it a little more and....... kablooie - the whole connection gave way, spraying me liberally with 60*C antifreeze. since I had'nt shut the pump down [I did'nt need to, I was only cinching it up a bit]. I eventually got off the roof after stripping off my soaking wet and very hot clothes [ I was in real danger of scalding myself], and stomped off to call the fitters. 'Oh dear. please send us a load of photos so we can advise you what to do next'. Well what I wanted was for them to explain how an 18 month old system costing several £K auto-destructs because of the failure of a 10p washer, incorrectly fitted by their expert team. 'We'll get back to you on that' So I wait in vain. Meanwhile a small cloud of steam can be seen coming from the now open-to-the-air system as the remaining coolant evaporates away............