Above is the system I have at present. Concorde WRS boiler, fully pumped, a single 2-port valve controlling the heating, a room stat and Potterton EP3002 programmer.
I can have the HW on on its own, but if I have the CH on, the HW also has to be turned on.
The diagram below shows the lives from the programmer. Would it be OK to run a new link wire from the switched live of the room stat to power the pump and boiler when the CH is on?
This would mean that I can have seperate control of CH and HW on the programmer, and won't have to have the HW on to make the pump and boiler run for the CH
(There is no pump overun on the boiler)