I have a question about installing HR80 TRVs with the CM Zone system.

My house has a two-zone system Ė one mechanical zone valve controlling the ground floor (5 rooms heated, 7 rads) and one the upper floors (8 rooms, 11 rads). The zone valves are wired to call for heat from the oil-fired boiler. Nearly all the radiators have conventional mechanical TRVs (Peglar Terrier II). Up until a couple of weeks ago the system was controlled by a conventional 2-zone 7 day timer switching the control valves on and off.

I have now installed 2 HC60NG controllers wired into each zone valve. Upstairs I have a CM67NG (which I brought from my old house) and downstairs a new CM927 (which I was mis-sold as the replacement for the CM67NG Ė I really wanted the two-zone CM67z).

The system was easy to install and works well. However I want more control over the temperature in individual rooms (at the moment if I want to increase the temperature in the living room I have to set a higher temp on the CM927 in the hall and then run around turning the other TRVs down (presumably upsetting the optimisation profile at the same time).

I presume the answer is to install HR80s and then add more room controllers (CM67zs). Iím also thinking about Hometronic but want to get the HR80s sorted first!

Iíve bought one to check if it will fit the valve head OK and to see how I get on with it. Iíll put this in the living room. My problem is that the installation instructions supplied with the HR80 are near useless. The CM900 system instructions arenít much more use either Ė they give the various parameters for different synchronisation modes but donít explain how the modes work. The Honeywell website is a masterpiece in chaotic web design (itís unbelievable how they manage to do it so badly) and even a couple of calls to the technical people at Honeywell has resulted only in being sent an instruction manual that explains it all Ė that turned out to be the same one as came with the CM900 pack.

What is not clear is what is synchronising with what and what to bind with what. I presume the HR80 needs to be bound to the CM927 so it can receive set-point information but also needs to be bound to the CN60 so it can call for heat, or does the HR80 send that signal back to the CM927 so that it calls for heat, or can it be done either way? Do I need to first set the CM927 to be configured as a synchroniser (6:Sn)? What exactly do the different Room Temperature Sensor Use parameters do (8:Su) Ė e.g. does setting it at 3 mean that the HR80 will call for heat directly to the CN60 based on the temperature given by its own sensor, but presumably receiving set-points from the CM927? Do I need to bind the HR80 to the CM927 and the CN60?

Also can I set the HR80 to run manually without receiving set-points from the CM927 but still calling for heat from the HC60 (I know I can manually over-ride but this only last until the next set-point)? Would I do this by binding only to the HC60 and ignoring the CM927? Would this affect the way the CM927 works with the HC60?

Any help on this or pointer to a document or a post somewhere that provides a more useful explanation of the setup options and procedures would be much appreciated!