Radiant off High Temp. (Calif.Radiant)

Alan(CaliforniaRadiant)Forbes

We've got a radiator job in SF; each radiator will have a home run to a centrally located manifold. The owners want radiant in their bathroom and I thought we could run a high temperature loop over to a closet near the bathroom and install a mixing valve.

I'm trying to do this without an extra circulator; to let the primary circulator do the work (it's only one loop; probably .4 ft. of head, 2 gpm), but all the drawings I see (Siegenthaler) show a circulator coming off primary-secondary.

Any ideas?



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DanHolohan

Check with Danfoss

They have a valve called FHV-R that creates a sub-zone off a high-temp zone by limiting the flow through the radiant circuit to achieve a maximum return water temperature. It doesn't require a circulator. You just bring the high-temp line into the tubing and the FHV-R sits on the return side, limiting the flow and returning the radiant water to the high-temp return. It's as simple as can be. I saw it in Europe and I believe they've brought it over here.

Dale

I think

what I would be concerned about is overheating the radiant bathroom if the wind was up against the main outside wall area. Of course an IO reset would lessen this as would you keeping the mixer set so the floor radiant water temp was on the lowest end. Since you're home running anyway if it were me I would leave the circ out but leave an easy place to put it on the header just in case. If you do run a separate circ will you use a slab sensor in the bath? Keep up the outside the box design ideas.

Alan(CaliforniaRadiant)Forbes

I should have figured

Danfoss would have something like that; they have some very slick devices.

I called my Danfoss rep.; he's digging something up for me. Thanks for pointing me in the right direction.

Best wishes,

Alan

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eleft_4

FHV

Alan,

Try these pdf files.


al

Bill Clinton

Radiant loop

While you can control the temperature of the room by controlling the flow rate, I question whether this is a good idea. What I think you would get is a quite obviously warm, maybe overwarm band of warm floor with the rest of the area remaining cool. The best way is to reduce the water temperature and for that you must have another circulator--no way to do it with a tempering valve.

bill

Dave Holdorf

Oventrop

has a control valve that can work in a system like this. It mounts on the wall like a thermostat and controls the flow with a two-way valve.

You might want to consider using reset on the entire system to lower the chance of over heating the bath.

If I find the info on that part, I'll post it.

Dave H.

Mark J Strawcutter

area limit?

They limit the controlled area to 10 sq meters. Perhaps this helps avoid the hot area / cold area problem.

Mark