Two stage heating question

Jason_Talbot

I wrote a post several months ago about how my radiant heating has been inadequate during very cold weather. Since we already have a spacepak unit serving AC to this floor we are now adding an auxiliary hydro-air heating coil to the spacepak unit.

My question is how to configure our thermostat (it's a current generation NEST) to optimally handle the second stage of heating. Currently when temp goes below 15F outside the radiant is unable to keep the room above 60F. We usually keep the set point at 70F. My thought is that if the radiant can't bring the room to the set point in a certain amount of time, or falls below a certain temp (say 65F) then the auxiliary heat would kick in.

My fear is that once the auxiliary hydro-air heat kicks in, it will quickly bring the room to temperature and lead to shutdown of the radiant. Is there any way to set the thermostat so that the radiant would just stay on while the aux hydro-air kicks in as needed if things drop below 65F?. And that only if the room reaches the set point without the auxiliary heat, will the radiant cycle off. Does that make sense? Can anyone advise me on this?

Thanks
Jason

gennady

Radiant system must work off floor sensor not a thermostat. set thermostat of auxiliary heating unit to 67F, and you will be ok.

njtommy

I'm not a Nest guy, but wouldn't the t-Stat figure it out do it being a learning/ smart t-stat?