# Oxygen barrier pex vs. no oxygen barrier



## headrc (May 29, 2008)

What are the opinions on this forum of oxygen barrier pex vs. non oxygen barrier pex for radiant floor systems ....or for any element of a hydronic heating system for that matter.  Thx again,  RH


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## deerefanatic (May 29, 2008)

There's no debate at all on that.. If you're using a closed system, you MUST use oxygen barrier pex... Or else your system won't be closed......

Now, on open systems, it's a little less critical.... Basically a good anti-corrosion additive is in order there if you have ferrous (iron based) materials in the system.

Frankly, for the small price difference, get the O2 Barrier stuff that way you're ready no matter what you do in the future... Pex if properly cared for (and of good quality) has a basically infinite lifespan, so do it right the first time and you'll be better off in the end... If you go with O2 Barrier pex now, in 35 years you will not even notice the price difference...


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## headrc (May 29, 2008)

Ok ....so it is an issue for oxidation in pumps etc. and the oxygen barrier helps eliminate that problem ....do I understand this correctly?  Now I have one problem ....in my design I have three zones that I will set up.  The problem I have is that the first zone is a concrete slab that now has pex in it without an oxygen barrier.  So this is a mistake ....and now cannot be changed .  Why did I do it?? Because I looked at several sites of vendors who marketed radiant floors and they did not sell oxygen barrier pex in their systems .....and did not indicate it was needed ....and of course I did not know about this site where I could get other advice.  So what do I do about this? I am thinking I could isolate that zone with its own heat exchanger and use the necessary components to combat the issue of the pex without an oxygen barrier ......then use pex with an oxygen barrier for everything else.  I assume then that the insulated underground pipe etc. also needs to be pex with an oxygen barrier as well ...is this correct?  Thx,  RH


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## deerefanatic (May 29, 2008)

You're on the right track. Another option is anti-corrosion chemicals.... Little more expensive in the long run though and must be monitored as well..... On the other hand, if you use an open loop stove (OWB, Garn, etc) then this is all moot as the system is open anyway.....


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## headrc (May 29, 2008)

I am using an OWB .....with heat exchangers to transfer heat to two radiant floor loops and one radiator loop ...and I was going to use chemcial to keep the ph of the water at the right level ....so do I still need to use oxygen barrier pex then?  Thx,  RH


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## deerefanatic (May 30, 2008)

It's always a good idea....... But, if you're using anti corrosion chemicals (these are not necessarily the same as ph balancers.... check out woodboilersolutions.com for a good product) I wouldn't worry about using another heat exchanger on the floor that has non-barrier pex...


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## headrc (May 30, 2008)

I thought I had a closed loop system ....but I guess because the stove is not pressurized this is what determines if it is a closed or open loop system?  Thx,  RH


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## deerefanatic (May 31, 2008)

Well, sorta.... See, from a pure standpoint, if water is able to evaporate from the system at all, then it is open... Only if it is completely sealed with a pressurized expansion tank is it really "closed".... The pressure doesn't make it closed, the sealed nature does..... But pressure goes hand in hand with being sealed....

No me for instance, I'm going with open topped expansion tanks which would make my system "open".... But I'm going to try and throw wax on top to make an air barrier between the surface of the water and the air above... So I'm theorizing that I can have a "closed" system without pressure..... I guess we'll see if it works or not...


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## solarguy (May 31, 2008)

Do your self a favor & use a heat exchanger for your non barrier pex tubing when connecting to a closed system. The money you spend now will big time offset what you're going to spend in a couple of years.


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## steam man (May 31, 2008)

solarguy said:
			
		

> Do your self a favor & use a heat exchanger for your non barrier pex tubing when connecting to a closed system. The money you spend now will big time offset what you're going to spend in a couple of years.



I am going to use a heat exchanger to isolate my radiant floor tubing from the boiler water. The pumps and materials will all be non-ferrous on the tubing side. This will allow me to use the solar at a lower temperature or wood/oil at a higher temp when needed.


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## deerefanatic (May 31, 2008)

I agree with these guys.... What I was simply saying was that if you already had an open system, then you need to address that anyway, so your non-barrier pex in the floor is not a problem.. But if the rest of the system is closed, then a Hx is in order for the non-barrier floor.


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## headrc (May 31, 2008)

What about using glycol ......will that help?  RH


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## deerefanatic (Jun 1, 2008)

Glycol is just an antifreeze... It actually makes corrosion worse.... Plus it really hurts efficiency of the system.. Anti-corrosion is what you're after... And that stuff is waaaaayyy  cheaper than glycol too......


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