I live in southeastern MA. We just installed a new high efficiency condensing gas boiler (an HTP EP-220). However, the contractor advised us against installing an Outdoor Reset Control (ORC). We have 5 zones (plus an indirect hot water heater). 4 zones feed baseboard heaters (1st & 2nd floors) and 1 zone feeds a radiant heated slab in the basement. The contractor said that because of the radiant slab, it's not worth installing the ORC. He tried to explain it to me but I didn't get it. My question(s): a) is it true that it's not worth it?; b) why or why not?