Hi Tony,
Thanks for that! What exactly does the Diverter valve do? (Excuse my ignorance - I'm more of a sparks!) I thought it diverted the water around the loop when no radiators were calling for heat. But I guess that's not the case. So how does it affect the simple operation of hot water...
I've just been reading the catalogue of problems people have been having with their Worcester 9.24 boilers. But none of them mention the problem I am experiencing. I can get SOME hot water when the CH is on, but basically the system is not firing up when Hot Water demanded. Any ideas?