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Connecting baseboard to ¾” pex

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Plumdog_2
Plumdog_2 Member Posts: 873
in THE MAIN WALL
when connecting baseboard. I use 1" PVC electrical conduit ells with the female end up; it supports the bend and you can stick in a straight scrap to protect it during drywall phase, then pull it out when time comes. You can solder sweat x compression to the baseboard elements up on your bench, then pull up on the tubing to get some slack, make your connection and push it back down carefully into the support brackets. I can run the pex rough twice as fast as copper, but it takes twice as long to hook up the baseboard.

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  • Ken C.
    Ken C. Member Posts: 267
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    An exercise in frustration!

    I dread it whenever I have to connect copper fin-tube baseboard heating element to pex tubing. It’s definitely faster to run feeds/returns/jumps in pex than copper, but when it comes time to make the connection to the heating element, pex is a pain in the butt.

    The ¾” pex never seems to come up through the floor straight. I’ve tried using a torch to slowly warm up the tubing, but then when you try to bend the tubing straight, it wants to kink.

    I’ve also tried using Pex-Al-Pex (Stadler’s FostaPex), but that is even more stiff and hard to work with. Since it only comes up though the floor a couple inches before it ties into the baseboard, you don’t have much leverage to try to straighten it out.

    Does anyone have any advice for making connecting ¾” pex to baseboard less frustrating? What techniques do you use?

    Also, I have questions about what size holes to drill. If I have ¾” copper stubs for baseboard, I drill a 1-3/8” hole, which is large enough to fit the copper tubing, plus a plastic mouse-ear clip where the tubing penetrates the floor. I’ve been using the same diameter drill bit for the ¾” pex, but because the pex wants to bend at crazy angles, it rubs against the hole in the floor. I’m concerned about noise when it expands.

    One company I used to work for used 5/8” heat pex (Wirsbo) instead of ¾”; that size is a little easier to work with, but most companies seem to use ¾” pex for heat.

    Any advice would be appreciated.
  • hr
    hr Member Posts: 6,106
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    5/8

    and sometimes even 1/2 PAP will be sufficient. Just depends on how many BTU you are trying to move. You might drop down in copper and make the connection below the floor if it is unfinished basement or crawl space.

    Yeah, 5/8 is much easier to connect.

    hot rod

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  • Ted_9
    Ted_9 Member Posts: 1,718
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    design

    Try designing with 5/8th then. Some pex providers have baseboard copper x pex 90s that make our jobs easier.

    On a similar note. I've yet to see data on how much copper fin the 5/8th will carry. I should look into that again. I usually go around 30 feet with 5/8th. How about you HR?

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  • lchmb
    lchmb Member Posts: 2,997
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    Drop down

    I usually drop copper down through the floor out of fear of the carpenters. I learned it the hard way when a flooring company drove a piece of wood in against the pex which was warm and sheared it off (no it wasn't easy for them to do, think they worked at it for awhile). I also use the 5/8th and have had no problem's with it.
  • EJW
    EJW Member Posts: 321
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    Baseboard

    Use 5/8" Heatway Onyx, its much easier than any pex. EJW
  • hr
    hr Member Posts: 6,106
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    With the Series Baseboard Simulator

    in Siggy's HDS I ran 80 feet of 5/8 PAP with 4 90° ells. 80 feet of SlantFin # 15 in 3/4", Grundfos 15-58 on speed one, moving 3.7 gpm. 35,000 BTU/with a 20.8 delta t

    hot rod

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  • Weezbo
    Weezbo Member Posts: 6,232
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    Howdy lone wrencher

    > I dread it whenever I have to connect copper

    > fin-tube baseboard heating element to pex tubing.

    > It’s definitely faster to run feeds/returns/jumps

    > in pex than copper, but when it comes time to

    > make the connection to the heating element, pex

    > is a pain in the butt.

    >

    > The ¾” pex never seems

    > to come up through the floor straight. I’ve

    > tried using a torch to slowly warm up the tubing,

    > but then when you try to bend the tubing

    > straight, it wants to kink.

    >

    > I’ve also tried

    > using Pex-Al-Pex (Stadler’s FostaPex), but that

    > is even more stiff and hard to work with. Since

    > it only comes up though the floor a couple inches

    > before it ties into the baseboard, you don’t have

    > much leverage to try to straighten it

    > out.

    >

    > Does anyone have any advice for making

    > connecting ¾” pex to baseboard less frustrating?

    > What techniques do you use?

    >

    > Also, I have

    > questions about what size holes to drill. If I

    > have ¾” copper stubs for baseboard, I drill a

    > 1-3/8” hole, which is large enough to fit the

    > copper tubing, plus a plastic mouse-ear clip

    > where the tubing penetrates the floor. I’ve been

    > using the same diameter drill bit for the ¾” pex,

    > but because the pex wants to bend at crazy

    > angles, it rubs against the hole in the floor.

    > I’m concerned about noise when it expands.

    >

    > One

    > company I used to work for used 5/8” heat pex

    > (Wirsbo) instead of ¾”; that size is a little

    > easier to work with, but most companies seem to

    > use ¾” pex for heat.

    >

    > Any advice would be

    > appreciated.



  • Nick_16
    Nick_16 Member Posts: 79
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    What a

    nice program Hotrod? Where did you get it? How much does it run?
  • Unknown
    Unknown
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    pex-BBD

    Why not use 3/4C x 3/4PEX cinch style elbows off of the BBD then all you have to do is slide the pex up through the floor and use the cinch tool.

    ...and you guessed it, they call it the cinch tool because it is a cinch to use :-)
  • hr
    hr Member Posts: 6,106
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    HDS program

    I use this program almost everyday for something. Go to www.hydronicpros.com for a demo.

    hot rod

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  • ScottI
    ScottI Member Posts: 4
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    Baseboard pex

    We just did a whole house in copper fin baseboard. I stubbed copper below the floor and put a pex adapter into a 3/4 copper ell. 2nd and 3rd floor verticles were also copper.We pexed the entire basement.
  • marc
    marc Member Posts: 203
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    siggys program

    Hot rod, I have been thinking alot about purchasing this design cd. what are your thoughts on it. thanks marc
  • marc
    marc Member Posts: 203
    Options
    siggys program

    Hot rod, I have been thinking alot about purchasing this design cd. what are your thoughts on it. thanks marc
  • hr
    hr Member Posts: 6,106
    Options
    By all means, Marc

    you should invest in this software. Besides being very easy to use it has a great selection of modules to design, or troubleshoot.

    I think you will learn a lot more about good design and the limits, or ability to change heat output by playing flow and delta t room games. This was probably the biggest eye opener for me.

    Also the ability to see how various glycol %'s change pump and expansioin tank sizes!

    Buy the package that includes both the 2nd edition Modern Hydronic Heating, and the HDS disc.

    The Hydronic Lego disc should be available soon to create nice drawings, see below.

    hot rod

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This discussion has been closed.

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