Im installing a ModCon boiler with outdoor reset into a split level house that had previously had aluminum fin tube radiators throughout. It now has three zones plus DHW. 1) Basement with 12 feet of slant fin baseboard 2) first floor with radiant tubing under hardwood 3)second floor with the original had aluminum fin tube radiators. I dont have a problem setting the outdoor reset curve for the radiators and baseboard but that will also affect the radiant. The way I see it I can go two ways with the radiant zone, either I install a mixing valve and set the water temp for 115+/- on design day and see what happens when its 50 outside and the reset drops the boiler temperature or I install a set point mixing valve and set it to keep the water temp for 115+/- always. Any help would be much appreciated.