when i turn hot water tap on the boiler makes clicking noise but does not ignite to heat water. When CH heating is on and then you turn hot water on its ok.

ian, December 2009

I had similar problem on same model in Dec. Although the problem for me was other way round. ie; heat hot water but not radiators.
I narrowed down the fault to the motorised valve that was stuck on one side (hot water).
Got new valve from Screwfix £79, replaced and all OK.
Just in time for xmas.
Good luck

Alan, January 2010