Thanks for your reply, he ruled out any obstruction in the pipes or problem with shower and narrowed it down to the boiler, probably control board. I think I'll call Biasi and see if they can give me rough idea on cost of repair. Tbf this plumber is a honest bloke and I've known him for years...
Hi, I have a problem with biasi boiler DHW supply but only to the shower. Kitchen tap and basin is running hot but shower is barely warm. I have called a plumber who changed thermostatic valve in the shower but it didn't change anything, he then took the shower off and run the hot water directly...