Cant get any hot water from my baxi combi boiler but it works when the heating is on?

Sounds like the diaphragm in the diverter valve has gone. Is this a 105e or 105 e instant as they are different diaphragms. As an add on re a previous contributors suggestion about opening the prv to release air etc tats one way of getting premature failure of the prv as its possible to ge system debris stuck in the valve causing weepage of system pressure.