I have a leak on the Domestic side of the Boiler
It is a Boiler of about 15 years old with an id plate of VCW GB 242 EH
I do not have an hand book on this boiler and need to be able identify the part that is leaking
It is on the left of the boiler at about 8 oclock and looks like three Black Metal Tubes

victor, November 2005

I had the same problem the three black tubes are your heat exchange system valliant made a stainless steel version to overcome this problem , i was lucky that my house insurance covered me for the £200 it cost to be rplaced . Hope this helps you

tom tom, November 2007