Robert Gammon wrote:
Steve Barker LT wrote:
We're getting ready to build a new detached shop and we're going to
"tube up" the slab for radiant heat. Could you give me the links to
the sites you are looking at? I need an online supplier for the
tubing and as much education as possible. We are going to do this
ourselves. Hopefully we'll drive it with solar panels in the future.


www.ourcoolhouse.com

Radiant loop is powered by a ground source heat pump

The issue with solar is daytime use only. Detached shop OK. Maybe not
out there every day. Probably not out there before sun up, and
probably back to the house before or shortly after sun down.

Be sure to check out insolation rates for where you live and size the
number of collectors to be able to meet a target 70F approx slab temp
in winter.

and to the OP

The Tagaki is likely to fire for 30 seconds to get the water temp up to
120F and then shutoff while you continue to circulate the water.
After 30 to 90 seconds of circulation, the water temp has dropped low
enough that the Tagaki will fire again. Remember the Tagaki detects
BOTH flow and temperature of its outlet water.

Keep in mind that the circulator pump will want to move the water much
faster than 1 GPM.

You will use ALOT of gas to do this, even though Tagaki does document
the application in their guide.

As a radiant heat source, I think a tankless will work better as the
heat source for driveway deicing than for keeping your slab warm.