Hi Guys, I spoke directly to Alpha technical team, they were very good, emailed a copy of the manual (for free) . Having described the problem to them they suggested the "o rings" on the paddle at the back of the diverter valve (the job for this weekend and I will let you know how it goes). Re the noises mine is OK now (just clic,clic,clic woof) but used to moan at the top of its voice when firing up in DHW mode only!!
Tim Mc
January 2008