hot water problem worcester 24cdi rsf

[bashlo]

could anyone help me . i have a worcester 24cdi rsf combi . the problem is when i turn the tap on for water the boiler fires up the water starts to get hot but the boiler starts to make loud banging and clanging noises then it seems air is bubbling back up to the header tank. if i dont turn the tap off immediately the boiler cuts out on over temp.the central heating side works fine.it is not the divrter valve as i have changed that at a cost of 105 pound

[htg engineer]

Could be that the gas pressures are incorrect.

Are you sure it has a header tank ?


htg

[bashlo]

thanks for your reply but solved the problem. heat exchanger blocked. clened it all out now ok