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radiant hot water ceiling heat question

wesPA Member Posts: 38
So, my brother in law and sister in law recently purchased a 1950's era ranch home. They told me the home had radiant heat. They wanted to open up a wall to increase area between the kitchen and living room and noticed copper lines heading up the wall. Turns out the home has the intact hot water ceiling radiant for the main level and copper lines in the basement slab feeding the basement with the Taco paneltrol mixing valves. All the valves appear to be open and no leaks that I could see at this point. (The make up water valve is open though)
Here is my main question. There are 4 sets of lines that run up the wall that they want to remove. My thought was not to mess with the original balance, and relocate each set up to the attic all together in the first bay possible. Each line is 3/8" ID (1/2" OD) copper. I was hoping to be able to convert to Pex in the basement and run all 8 lines bundled in the same bay up to the attic, and then reconnect to each individual line. Would anyone have any recommendations on any easy way to connect the 3/8" ID copper to the pex and for a particular type or brand of pex/fittings that would best for this would be very helpful. I also thought of capping all the branches in the basement and running 1 set of mains up, but was worried about disturbing the balance of the rest of the system. Any advice, input, or suggestions would be extremely appreciated. Thanks!


  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,077
    edited September 2022
    Your plan sounds good. I would pipe either two 1/2" supplies and returns or one 3/4" to feed the two 3/8". You can use a 3/8" x 1/2" copper reducer and then a 1/2" copper x PEX adapter. Uponor, Mr. PEX are good bransds.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • hot_rod
    hot_rod Member Posts: 22,396
    Maybe run the system first and look at the ceiling with an infrared camera.

    That will show the layout and spot any leaks
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,364
    Hi, I would not bundle the lines unless they are insulated individually first. Otherwise you’ve just built a heat exchanger 🤠
    Yours, Larry