Is outdoor reset applicable for me?

Jeff Patrick

I've got hot water radiant in my home: 1/2" pex in 1 1/2" gypcrete with 3/4" oak flooring (real wood not an engineered floor). I've got the mixing valve set to its lowest setting which gives 85+/- degree water to the floor. It returns 10 degrees colder. Right now I using a standard on/off wall t-stat. The house can get plenty warm, no problem there. In fact last winter the floor was too warm causing some shrinkage in the oak, since then I've turned down the mixer. We get wider temperature swings than I'd like since the response time is so slow. So, I'm considering both outdoor reset and a much smarter thermostat.

I understand the primary benefit of outdoor reset is that the system can sense a drop (or rise) in outdoor temp and then increase the temperature of the water delivered to the registers, floor, whatever. But, since I do not wish to allow the water temp to go above 85degrees.... wouldn't that negate the outdoor reset benefit?

I'm thinking that a smarter thermostat that can sense both the room temp and the floor/slab temp will be a good thing. I know that if I manually turn off the system when my feet feel the floor is warm the room temperature will soon follow. If I allow the wall t-stat to turn off the system, it will put too many btu's into use and thus the room temp goes too high. I'm considering the Tekmar 509 or 511. What do you think?

carol_3

tekmar guys, what do you think?

Reset usually changes your boiler temp to save money on maintaining the standby water temp when the weather's warmer. Your mixing valve should deliver the same temp to the floor no matter what the boiler temp is.

Could be that your floors didn't shrink because of the water temp but because of your air humidity level. I don't have in-floor heat (alas) but my oak floors get creaky in mid winter because the humidity in the house is low. If I use my whole-house humidifier, no problem.