hydronic floor heat question.

[stealman]

Can I put the supply and return pipes that go to the manifolds in the concrete slab?

 

[Chris705]

Not sure I would recommend that you put them in the concrete. I ran my supply for a future snow melt system under my slab and it’s insulation. I ran 1” pex in armaflex and wrapped it in heavy plastic. This will allow me to run hotter temps to the manifold and use a mixing valve to get the desired temp. Will your heating plant be able to deliver exactly the temp fluid you want to run in your floor? What size tubing did you intend to put in the slab to feed the manifold, would you be concerned about crossing over the pex loops? If you ran the supply and return lines under your slab & insulation you can run in a straight line from heating plant to manifold location.

 

[stealman]

I dont think the heater will deliver the correct temp. I was thinking I would run 3/4" pipe to the manifolds and 1/2" pipe in the floor for the loops. It looks like running them in the slab is a bad idea.

Do I need a separate supply and return for each manifold?

 

[Chris705]

Not sure exactly, are the manifolds serving the same zone?

 

[Jackfre]

Are you running pex to the manifolds? If so, you could install some 3 or 4" PVC or ABS below the slab. Use sweeps rather than 90's. Make sure the big inch is water tight and your 1" pex is insulated as it is fed in.De-burr the big inch. Otherwise your insulation will get torn up. I would use 4" myself.

 

[stealman]

The guy that is helping with the design of my system says that putting the supply and return for the manifolds in the concrete will not be a problem.He says that the temps will be similar in the manifold supply and in the loops. The floor just might be warmer in the location of that pipe. It will be easier to put them in the slab, but I dont want to sacrifice system performance.