ace high dhw?

I have seen other postings talk about the diverter valve which must be in the flow body. I notice that i will get DHW when the CH is on so there must be a flow between the two which is not right. Does this point to the diverter or still a diaphram problem?.
Does anybody know how to change the diverter. I have the manual but it does not show an exploded view of the internal parts of the flow switch.