Radiant Floor Heating and Loop Design

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Old 03-12-14, 07:34 PM
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Radiant Floor Heating and Loop Design

I have a basement area that is about 285' that I am considering installing 1/2" pex tubing with 10" spacing into about a 3.5" concrete slab. That calculates to 342' and the maximum loop length is 300' so I am forced to install 2 loops.

I was thinking, instead of me splitting up the room into 2 sections for the 2 loops (plan a), can I space 20" loops and overlap so that there is tubing every 10" as I am wanting (plan b). Is this done or is my OCD taking over?

Any help here is appreciated. Thank you in advance.
 
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Old 03-17-14, 01:44 PM
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you can do it any way that you want.
Personally I would do 9" centers in your slab... 10" might work out better with room dimensions.
Split the room up so you have equal tube lengths to make balancing easy.
If you do it with design b, the interweaving loops, then where loop a is the supply make that same start point the return for loop b. This will all help to try to ensure even slab temperatures.
 
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Old 03-20-14, 11:30 PM
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Thank you TOHeating..

I also ran into this very informative page from Wirsbo.Name:  tubinglayout.jpg
Views: 1810
Size:  51.2 KB

It can also be seen here http://www.uponorpro.com/~/media/Ext...spx?sc_lang=en
 

Last edited by zizanio; 03-20-14 at 11:54 PM.
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Old 03-22-14, 01:03 AM
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Name:  loopdesign-double.jpg
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If you do it with design b, the interweaving loops, then where loop a is the supply make that same start point the return for loop b. This will all help to try to ensure even slab temperatures.

Read more: http://www.doityourself.com/forum/bo...#ixzz2wg0PUCb1
Is this what that translates to? Kinda like a double loop serpentine with more evenly distributed heat. The only thing is, I have 2 outside walls and an unheated garage wall that maybe I should be considering a different layout.
 
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Old 03-22-14, 04:05 AM
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Here is a suggestion. If you put in shorter loops your water stays hotter a it gets back to the manifold. Put the hottest water on the outside walls and you can put the tube spacing closer together. The outside walls is where you need the most heat. Just my thoughts.This is just a crude drawing. I have it done nicely in pencil but pencil does not scan well.
 
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Old 03-22-14, 06:03 AM
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Here is a suggestion. If you put in shorter loops your water stays hotter a it gets back to the manifold. Put the hottest water on the outside walls and you can put the tube spacing closer together. The outside walls is where you need the most heat. Just my thoughts.This is just a crude drawing. I have it done nicely in pencil but pencil does not scan well.

Read more: http://www.doityourself.com/forum/bo...#ixzz2whDEWtqT
I have 285 square feet of area to heat, at 9" center loops that 380 feet of tubing. split that in 2 its 190 feet per loop. The maximum for 1/2" is 300. I think 2 loops is adequate.
 
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Old 03-24-14, 05:32 PM
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If you put the hottest water to the out side walls you will have the greatest heat loss to the out side , why would you do that ? I would put my hottest water in the center of the room and let the heat move to the cold . Just my opinion .
 
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Old 03-26-14, 06:24 PM
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The object of heating is to overcome the heatloss of the building, and therefore make in comfortable.

Your heatloss is on the outside of the building, not in the middle.
If you overcome the loss at the outside, then you would need heat in the middle of the room.

Tighten up the loops at the exterior walls, feed it with the hotest water.
 
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