We've just installed a new Condensing Combi boiler last week, Lochinvar NKC199N. I've noticed the installer set the outlet temperature to 180F/82C and the return temperature to inlet is somewhere around 169F/76C. To me, this temperature set point is way to high but with the fact that it was cold out side last week 5F/-15C, we are in Massachusetts.
We have 4 zones, 3 zones control forced hot water baseboard and the other zone controls radiant floor (concrete slab for our greenhouse, we use a mixing valve to reduce water temp to 130F/54C for floor). So while the other 3 zones satisfied the room temperature, the 4th zone for the radiant floor seems to keep running most of the time to keep the slab warm with this cold temperature outside, but since the outlet set point is 180F/82C, I feel that we are wasting the energy.
So my question is should I change the outlet set point to 130F/54C? so we can just send 130F/54C straight to radiant floor, ignoring the mixing valve, and I expect the return temperature to drop to somewhere 110F/43C, so it can be condensing. Is "130F/54C" good enough for baseboard heater?