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Re Gravity conversion

Layth Member Posts: 18
edited June 2022 in Radiant Heating
A quick update. I have drilled almost all of the holes to reach my 14 convectors ( all homeruns ) and removed almost all of the 28 1/2" feedlines ( thanksMattmia2 ), allowing me to screw in my type A pex adapters. This where I am now.
I have a question I ask with fear and trembling. Before this project I replaced all of my old pluming with type a aqua pex from Uponor and without thinking used my left over pex to complete two radiant zones. One under the kitchen floor in a 4' crawl space ( I still have nightmares) and the other in a more open space under the rest 0f the kitchen. This is not oxygen barrier pex. My question is, will I be all right if I use stainless steel pumps? It is worth it to me not to have to go back in that crawl space pull out all the insulation and redo everything. Are there other concerns besides the pumps?

Thanks, Tom


  • GGross
    GGross Member Posts: 703
    The oxygen will attack ferrous metal components of your system. Usually we see this in the circulator, however other components can also be impacted. the best way to solve the issue long term (in my opinion) is to separate the non-barrier from the rest of the system with a heat exchanger. Anything on the non-barrier side of the heat exchanger should be stainless/brass.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 6,119
    edited June 2022
    I'm not familiar with your project or what boiler you are using, I will read up on that after i give your this.

    If you have a cast or steel boiler or any cast iron or steel parts like flow control valves, expansion tank, fittings or air scoops, then you must also change them. Or you can just change the tubing to O2 barrier PEX. What ever is easier.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics