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[doo_hicky]

Im having a hard time wrapping my head around what is all going to be needed for a (hopeful) in floor radient install in half of my pole barn.  The insulation, wire mesh, and radient barrier are easy.  I have 900sqft so a 4 loop manifold will be what i should need.  Not sure on the size of the pex and the plumbing for the mixing valve and that stuff. I have a pressurized system, so either Pex-al-Pex or OB pex is what i need to use.

Pictures would be a HUGE help.

Thanks

Mike

[Sprinter]

Oxy barrier for sure, .......radiant barrier? What are you using?  Hopefully you meant foam board. 2".... I would go 6" oc which is about 1600' of 1/2" pex.. 5/8" @ 9"oc is 1200' pex. Try to keep loops at 250' , longer than this creates inconsistencies or requires over pumping to hide. Also you want your mesh or pex on chairs so it's within 2" of the top of Crete. This reduces lag time greatly and also allows for fewer btu and lower supply temps.

Don't forget to insulate the edges as well this accounts for 15-27% of losses. I would do a standard layout not reverse return since this is a barn. Meaning the hottest goes to the perimeter and works toward the center. Don't be afraid of going shorter loops and more loops. It can't hurt, but too long can hurt. This gives you much more control and flexibility. Maybe you section off a room and want more heat there, just balance the manifold to do so, for example.

[LittleJohn]

Lay it out correctly once, cause its a bit harder to fix after the concrete goes in!   

Also, pay attention to where exterior doors are, it can be beneficial to run a little bit closer spacing in these high heat loss areas

[doo_hicky]

What about the mixing valve, and how it is plumbed?  This is the area that i am most concerned with.

[slimjim]

  Guys if you go to your local plumbing supply house that you buy the components from, they will lay the whole thing out for you at no additional cost, this makes them responsible if you have a problem, take their advise and do it the right way

[NaturallyAspirated]

What about the mixing valve, and how it is plumbed?  This is the area that i am most concerned with.

You need something like this:

http://ecomfort.com/pre-assembled-fixed-point-manifold-mixing-station-5-outlets-thermostatic-fixed-point-mixing-flow-gauges-34-ball-valves-67108.html?utm_source=amazon&utm_medium=product_search&utm_campaign=amazon&utm_content=67108

Neal

[LittleJohn]

Doo_hicky, when installing a mixing valve it is the general rule that you need a pump some how plumbed into the mix temperature line.  This is what will push the water from the mix valve out thru your floor; depending on style (have seen a few 4-way mixing valves) may require an addition pump on heat source loop.  But in most cases, the mixing valve should come with some paperwork explaining the manufacturers recommended installation method