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Can Pex be fished through copper ?

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delcrossv
delcrossv Member Posts: 781

May have a radiant floor leak, was wondering if there's any hope of fishing pex through the old tubing or if I'm doomed to chipping up the floor or abandoning the radiant and putting in fin tube.

Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.

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  • DCContrarian
    DCContrarian Member Posts: 301
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    PEX has the same size as copper, so you'd have to go down a size, which may not support the flow you need. A piece of 1/2" PEX will fit inside of 3/4" copper although I don't think you could get it to go around an elbow. You can try for yourself. The bigger problem I see is the PEX won't make good contact with the copper so you won't have good heat transfer.

    I think you have to abandon the copper.

    Mad Dog_2PC7060Ironman
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,241
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    Consider raising the floor and go right over the old slab with pex & a mud job. Some new saddles, cut down your doors...Mad Dog 🐕

  • delcrossv
    delcrossv Member Posts: 781
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    Nah, it's next to a zone that's still working.

    I'd probably run fin tube along the exterior wall and abandon the radiant 😞

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • mattmia2
    mattmia2 Member Posts: 9,944
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    I'd probably use panel radiators of some form rather than fin tube, they will at least produce some radiant heat.

    delcrossv
  • jumper
    jumper Member Posts: 2,331
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    ditto. Plaster & painting may be involved but mounting panels at ceiling height works even better. And if it's only one room electric is easier.

  • delcrossv
    delcrossv Member Posts: 781
    edited July 1
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    I have room to fit Runtal strips up to 3 high. No room at ceiling height though. Great idea! Thanks!

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    mattmia2
  • hot_rod
    hot_rod Member Posts: 22,472
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    Ceiling radiant, radiant walls, panel radiators. are other low temperature options.

    What tuype of boiler? Unless it is a mod con, go with high temperature emitters that take less wall space. High output baseboard maybe?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Intplm.
    Intplm. Member Posts: 2,083
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    I'm guessing NO. The current piping is probably too small in diameter to act as a sleeve.

    You will probably need to abandon that zone and add a new zone on the current floor.

    Or jackhammer the floor.

    delcrossv
  • delcrossv
    delcrossv Member Posts: 781
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    Old school hot water. Still has the B&G 100 circulators.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • delcrossv
    delcrossv Member Posts: 781
    edited July 2
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    I'm liking the Runtal panel idea. Can I run those at high (180-190 degree) temp?

    Seems so. And they're available with both connections at one end! 😃

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • dko
    dko Member Posts: 642
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    Type C connections are made-to-order rads with usually 8-12 week lead times so I would order way ahead of time!

    delcrossv
  • Intplm.
    Intplm. Member Posts: 2,083
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    Uponor makes something called a "Trak" system that should work if you want to abandon what's there now.

    Give Uponor a Google look for the specifics.

    delcrossv
  • pecmsg
    pecmsg Member Posts: 4,952
    edited July 4
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    what makes you think whatever caused the failure isn’t happening in the working section?

  • delcrossv
    delcrossv Member Posts: 781
    edited July 4
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    It's in a slab so that won't work. Needs to be some kind of baseboard. But thanks for the suggestion.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • delcrossv
    delcrossv Member Posts: 781
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    It probably is, but that section was put in 30 years later. If it ain't broke….

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • mattmia2
    mattmia2 Member Posts: 9,944
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    You can run it at 190 f. You may get more expansion noise the hotter you run it and the more it cycles on/off vs just an outdoor reset temp matched to the load.

    delcrossv