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Post by jjzahn on Aug 4, 2010 15:34:46 GMT -6
Hi, I am installing radiant heat in a second floor addition on my house. I ran 2 loops of 1/2" pex (Watts HeatPEX or RadiantPEX or something). My buddy is a heating guy and the son of a well known local HVAC man. I asked him if I could put the manifold on the second floor to save waste of pex to and from the second floor. He asked his dad, who replied that he wished that he would have done it that way in his own house. However, they say that the supply and return tubes to the manifold would need to be 1". Does this sound right? All the manifolds that I see only have a 1/2" inlet so I would need to use reducers from the 1" pex to the manifold WHat gives? Thanks, Josh
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Post by Christopher on Aug 5, 2010 6:43:19 GMT -6
Josh, are you using one of our stainless steel manifolds? If so, then yes the supply and returns are probably 1" (we also have 1-1/2", but I doubt you have that).
What do your manifolds look like?
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Post by jjzahn on Aug 5, 2010 8:06:59 GMT -6
I don't have the manifold, yet. I'm going one step at a time. Currently trying to finish covering the subfloor so I wanted to make sure the pex would be the right size before I covered.
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Post by Christopher on Aug 5, 2010 11:05:42 GMT -6
You'll want to run 1" supply and return to the location where the manifold will be then. Since you only have two loops of 1/2", I'm assuming your total flow will be under 12 GPM.
The circuit connections coming from the 1" supply and return trunks will be 3/4", and you'll then purchase the correct fitting to go from those to your PEX+, in this case 1/2". You can do either compression or crimp.
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Post by jasonbold on Aug 9, 2010 9:49:05 GMT -6
I think you can use the 1/2" to 1" pex fittings but in that case you will lose pressure at the outlet. Am I right?
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Post by Christopher on Aug 10, 2010 6:44:40 GMT -6
If you go from 1" down to 1/2" your water velocity is going to change one way or another. If your GPM is meant for the 1" pipe, it's going to be zipping through that 1/2" pipe pretty quickly and probably cause water hammer. If the GPM in the system is meant for the 1/2", it's going to be super slow in the 1", which will drop your pressure there, yes.
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Post by jasonbold on Aug 10, 2010 8:37:43 GMT -6
thanks for detailed response!
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