boiler hot water

comb system, heating on water gets hot, water only on does not fire up for long boiler feels hot but no heat in cylinder turned themo on boiler right up no good can some explain how it should work ie water is fed from tank in loft to ?? then goes to ? and so on

Read the third post at the top of the forum. Then answer the questions. Then put as much effort into giving us some information that you would expect in a reply.

If you think this is rude, it's not half as bad as I'm thinking, or your lack of punctuation. If you think that's picky, just remember you want some help.

sorry for my writing skills, or lack of.
i can not find this as your reply (Read the third post at the top of the forum) so what my problem is that when i activate water only nothing gets hot when i switch to heating and water its fine (apart from everyone in the house been rather hot) i have checked the pump its fine, i have checked the header tanks and ball cocks they are also fine so to heat the water does the pump send water into the coil in the cylinder and then just heat water only and not rads?
thanks from mo
p.s heating and water on now very hot in here

Click here for questions. It sounds like a valve problem, but we need more info. about your system.

faulty three port valve