With all the water treatments I am reading about is it really necessary. I am having a really hard time wraping my mind around the the fact that a material I can put heated water through under up to a 100 or so pds of pressure will let in enough oxygen to make a difference. For that matter a product that you can fill up with air under pressure and it will hold it, will allow oxygen to move through it? Isnt pure oxygen a gas? If I filled pex pipe with pressurized oxygen from my torch bottles is it going to leak out? Or is this just a marketing gimmick?
There is no question that O2 will get through the non barrier tube and cause damage. It is not a marketing myth. We have years of ctual data and failed systems to prove it.
Of course it depends on how much tube you are talking about and the temperature of the fluid. The hotter the fluid the more it allows the O2 ingress. We have first hand experience with steel expansion tanks rusting away and pin-holing within a year or two on non barrier tube systems.
Have you noticed tire dealers pushing nitrogen instead of compressed air? Same reason nitrogen replaces skinny O2 molecule with fat nitrogen molecule
It also helps with moisture which goes into your tire with of compressed air.
Hydronic and DHW expansion tanks are filled with nitrogen at the factory as they also have rubber or EPDM membranes and eventually lose their pre-charge pressure to the water if filled with compressed air.
Heatway tried for years to deny this was possible and now, under the Watts brand has added o2 barrier to their rubber and pex heating tube. There are thousands of radiant systems that sludged up due to non barrier tube allowing the components to corrode and rust away.
But you can address it with chemicals that include O2 scavenger, they will need to be maintained and boosted from time to time. Just as you would, or should with open system steel tank OWF and other open type boilers.
Or you could use all non-ferrous components with non-barrier tube. A stainless steel or bronze pump, and a DHW expansion tank, which are lined inside. Of course all the fittings, valves, etc need to be non-ferrous. When you add the cost of all non ferrous, or ongoing chemical treatment the small cost difference for barrier pex really pencils out.
Any thoughts?