adding zone control to combi boiler

[bonesy60]

I have just brought a new house that has a one pipe system installed so need to re-pipe. I am going to do a loft conversion and what I would like to do is to have three zones one for each floor. Can I switch them on and off and control the temps on each floor I know I need to run flow pipes with two port valves to switch each floor on and off but can the returns mix together at any point or do they need to be at a certain point like the return from the hw circuit. Thanks for any help in advance Ian.

 

[Puddle]

Set out flows through motorised valves as you say ,with their own room thermostats to suit

As regards concerns about any back feed to other parts of the system ,I would not bring separate returns back to the boiler, due to extra heated pipe runs involved, thus extra inefficiency, I would just link them back into a communal return and fit non return valves on each floors return pipework to eliminate the back feed problem, as we used to do with back boilers, when one half on gravity


ps ...please make sure motorised valves for floor zones are accessible for maintenance ,have spent many happy hour lifting carpets and floor boards trying to find and repair them

imho