Following on from all the CH questions that are asked here , I was bought a very useful book for Christmas called
Central Heating : Fault Finding & Repair by John Reginald
I originally borrowed a copy from my local library and must say that it is very useful (I had a problem with a motorised valve and it gave me an answer )
I know that answers can usually be found on the Internet somewhere ( such as this board) but I still prefer the paper "workshop manual" approach when trying to sort out any problems.
It`s a wonder that Haynes haven`t brought out a similar book....but perhaps they already have !
Scott