Radiant heat - temp switch and other temp Qs

[Borjawil]

32*40 pole barn -(3) 200ft 1/2" pex loops - energy king wood boiler

I'll need to get the exact model but ekb40 sounds familiar. A bit older but works well. I do not have ceilings in yet and I believe that may be an issue keeping things warm in my shop.

1) my switch, to turn off the blower and turn on the circulation or water pump, at its lowest settings is about 130 for the blower and 100-120 for the water pump. At least when they kick on or off.

That being said Ive gotten mixed information on the heat at which I want the water to be when going through the loops. Some have said about 100 degrees is good, others say 160-180 is fine.

Thought process being 100 degree water enters loops and comes back say 90 degrees as it shouldn't drop that much. So the pad would be kept at 90+ degrees correct? How does that translate to air temp? Heat rises. I have plastic over my peak vent and overhang vents. It helps until I can get a ceiling in, but I understand a lot of heat will rise to the truss area.

2) I plan on running a loop to my furnace in my home, and a loop through my driveway when I get it poured.

Driveway loop not an issue, but furnace loop...at what temp do I want this?

3) if I need water to be at 100 or less when entering my loops - I'm assuming I'll need a different temp switch? If so what am I looking for?

 

[Borjawil]

Found this for an aquastat which I like for the wifi capability in order to keep track of what's going on and I can set the blower and pump where I want it. Thoughts on something like this?

 

[Tonty]

I’ve been told to keep water temp 100 or below in a concrete slab. You can use a mixing valve to do this, your water temp in the boiler can be higher than 100, the mixing valve mixes some of the cool return water with the supply water to keep it at whichever temp you set it at.
Just because your water returns at 90 doesn’t mean the slab is 90. It may not have time to absorb that much heat, depending how fast your water is circulating through. You can use an infrared thermometer to shoot the floor temp if you really want to know what it is.
Do you have antifreeze in your boiler water? If not, you may want to use a plate heat exchanger for the outdoor loop, so that you can have antifreeze in the outdoor slab loop.
I don’t have a mixing valve on my furnace heat exchanger. So it runs at whatever temp my boiler water is, which ranges from 120-212.

 

[Borjawil]

Thanks for the reply, makes sense. I'll have to look into what I need in order to mix the return water.

 

[pettibone]

We have a radiant slab in our kitchen and run the water through a mixing valve to about 100- 110 max. The floor is usually about the same temp as what the thermostat is set for. A line between the return and the mixing valve is how ours is hooked up, pretty simple.