pex to radiators

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It won't cause air by changing pipe size. It won't cause condensing either.

Stick to HePex or PAP. Something with an O2 barrier.
1/2" tube will carry up to 15kbtuh dependent upon length of run. TRV's on each rad with a homerun sytem and constant circulation would be a fine way of zoning minute loads.

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  • pex to radiators

    I am removing all the piping in the basement of a house.The piping is feeding forced hot water radiators no the average radiator is 8 sections 36" high mostly all getting fed with 1 1/4 black.now if the radiator is under 25,000 btus is there a problem if you run a homerun system back to boiler room and seperate shutoffs for each one.does anybody have any pics on this and boiler piping correctly.
  • Timco
    Timco Posts: 3,040


    is there a reason you need seperate home runs? typically for a zone there is one loop, and the rads tap off of it, with a rad at the end of the loop, or for smaller loops, you can series them. if you series them, you cannot turn down an individual rad without affecting the entire loop. Pex cannot be used unless it is a barrier type. Copper works best, I found.

    T
    Just a guy running some pipes.


  • IS there a problem with running 1/2 pex to 1 1/4 black.Will there be a problem with air in the line because of enlargment of pipe.
  • Timco
    Timco Posts: 3,040


    Besides the obvious flow restriction, possibly adding to condensing, the pex will allow oxygen into the system when it heats up if it is not barrier pex. The rads and system will rust fast.

    T
    Just a guy running some pipes.


  • sorry i meant hepex


  • Note the high recommendation of TRVs in that article!

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