constant flow system operation with Tekmar controller

RonV_2

I need a bit of help to understand my heating control system to help me make a small modification.  The system uses a Tekmar 363 controller with outdoor reset.  It controls a single mix zone using a 4 way mixing valve.  The system receives zone air temperature feedback from a Tekmar RTU, and the heating demand is hardwired ON all the time, so this is a constant flow system.  The mix zone circulator is a Wilo  Stratos that is left on all the time and set to deltaP-V mode.





 My question is, does the Tekmar controller control a linear feedback system in my configuration?  In other words, when it has heated the zone to its target room temperature does it then attempt to hold the mix supply temperature at just the right value to balance gains vs losses and in so doing hold the mix supply temperature fairly stable?





 Or, does it swing the mix supply target temperature over a

wide range (like, for example, from its mix target value back to its Mix Min value, which in my system would be many tens of degrees)? 





 What I want to do is to create a small zone out of one of the bedrooms by separating its radiant tubing from the main zone by a zone valve back at the manifold.  The zone valve would be actuated by a thermostat in the bedroom.  This valve+thermostat would have no ability to place a demand on the controller.  I believe that this would allow me to run the room a bit cooler than the main zone.  I figure this should work

smoothly, but if the mix supply temperature is varying widely it might not be so smooth.