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Heating pex tubing

HeelteeHeeltee Member Posts: 19
Going to use pex tubing for the first time. I am installing a new hot water heating system in my house. Any suggestion on what I should be aware of ? What are the best tools/fittings to buy ,etc etc.I will be using the old cast iron radiators. Thanks!


  • Steve WhitbeckSteve Whitbeck Member Posts: 669

    If you are going to use the old cast iron rads - the PEX MUST have an oxygen barrier or anything that can rust will - within a few years they will be swiss cheese.
  • SWEISWEI Member Posts: 7,356
    PEX systems

    Like Steve said, barrier PEX for sure when there's any iron in the system.

    Systems consist of fittings, tooling, and (to a lesser extent) tubing chemistry.  ASTM recognizes the following:

    ASTM F876 Standard Specification for Crosslinked Polyethylene (PEX) Tubing

    ASTM F877 Standard Specification for Crosslinked Polyethylene (PEX) Plastic Hot- and Cold-Water Distribution Systems

    ASTM F1281 Standard Specification for Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene (PEX-AL-PEX) Pressure Pipe

    ASTM F1807 Standard Specification for Metal Insert Fittings Utilizing a Copper Crimp Ring for SDR9 Cross-linked Polyethylene (PEX) Tubing

    ASTM F1960 Standard Specification for Cold Expansion Fittings with PEX Reinforcing Rings for Use with Cross-linked Polyethylene (PEX) Tubing

    ASTM F2023 Standard Test Method for Evaluating the Oxidative Resistance of Cross-linked Polyethylene (PEX) Tubing and Systems to Hot Chlorinated Water.

    ASTM F2080 Standard Specification for Cold-Expansion Fittings with Metal Compression-Sleeves for Cross-linked Polyethylene (PEX) Pipe

    ASTM F2098 Standard Specification for Stainless Steel Clamps for Securing SDR9 Cross-linked Polyethylene (PEX) Tubing to Metal Insert Fittings

    On balance, I'm partial to F1960 (aka Wirsbo) but there are things about the others I wish it had...
  • ZmanZman Member Posts: 3,476

    Pex-a or pex-al-pex are probably your best choices.

    I like uphoner hepex with propex fittings.

    Like Steve said o2 barrier is a must.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • bob eckbob eck Member Posts: 560
    Pex tubing for heating

    Take a look at using Viega fostapex pipe. It is a full size pext tubing that has a aluminum over the Pex and that works as the oxygen barrier for this tubing. This tubing will not grow in length or droop when hot boiler water is run through it. I used it in my house to run to cast iron radiators and it worked great.
  • HeelteeHeeltee Member Posts: 19

    Thanks ! To all I Will use info.
  • bill nyebill nye Member Posts: 307
    Piping method

    Heeltee Heeltee, how were you going to pipe your system? Radiator to radiator in a series does not work so well. I have had good luck with the homerun method where you supply and return your radiators to a manifold or a monoflo system. I am doing one now in a 100+ y.o. house. We did a copper monoflo loop and will do take offs to rads with pex
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