Adding radiant floor to existing zone?

Adam E

Hi all,

I'm remodeling my kitchen and am losing almost all open wall. Right now I have a cast-iron baseboard monoflo system. The house has three zones with zone valves on the supply side and one Taco 007 on the return.

I'd like to put radiant floor (between joists) in the kitchen while keeping it on the same zone it was on (with the living room and dining room).

I know about the need for a mixing valve and flo-check, etc.

From what I understand, I need a separate pump for the radiant floor and the one diagram that I've seen for my hookup shows no new zone valve needed. See it here in the fourth diagram down.

http://www.radiantcompany.com/system/closed.shtml

This shows my exact setup (without the radiant zone), except my ZVs are on the supply side and I have three zones.

How would I wire this so that T-stat #1 fires both pumps and T-stats #2 and #3 fires only the one?

If I need a zone controller, which one? How about pump recommendations? There will only be about 200' of Pex.

Remember, think inexpensive!!!

Thanks!

Adam

Joh n Brickey

I saw your post on another sight. I agree with some of those answers,you could put some open fin in between the floor joists and pan them off. I've done this before and it works well. You could also get a toe space forced air unit under your cabinet. With the open fin or the toe space you could leave it on the same zone as before. If you put in floor heat you could leave it on the same zone if you put in a bypass and mixing valve. There is a new product out now that I'm trying called Ultra-fin and it requires 160-180 degree water,this might be worth looking into.

adambuild

We have successfully accomplished exactly what you are trying to do several times. You can tie the new radiant loop into the existing CI radiator piping in the basement. You'd control the circulator that pushes "the mix" with a Honeywell aquastat #L6006C1018. Its probe clamps to the supply side. When that floor's zone gets hot, the aquastat will turn on the circulator. Voila! Cozy toes!

Adam E

Wow, that sounds simple and great!

My next question is, how long does it take for you to feel heat once you thermostat calls for it? I was just thinking that by the time the thermostat in the living room is satisfied, the radiant floor in the kitchen will just be starting to get warm. Then, about the time the floor is cooling off, the thermostat will call for heat again.

Does this staggered effect cause problems?

adambuild

You can only heat efficiently or evenly using the method I described if the balance of the heating medium on that zone has a very similar thermal mass. In other words, the new radiant has to heat up and cool down in a similar amount of time as the existing CI baseboard. Otherwise, if you had fin tube baseboard for example, the radiant would barely get warm because the fin tube would heat the other rooms too fast, thereby shutting down the heat before the radiant gets a chance to heat up. Good luck, Adam