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copper pipe

Capt.Dan Member Posts: 19
What type of copper pipe should I be purchasing for my heating connections?, type M or L and can you tell me the differences? Thank-you. CaptDan


  • Wild Bill
    Wild Bill Member Posts: 112
    Copper tube


    "M" wall copper tube has a thinner wall thickness than "L" wall copper. I believe the entire country allows "M" wall for heating. However, some people prefer to use L for several considerations. For example, noise reduction, not as "spaghetti like" more resistant to aggressive water conditions. For the small price differeence, I would "go to L".
  • jackchips_2
    jackchips_2 Member Posts: 1,338
    Ten hut!

    I have never seen a problem with M on a FHW heating system but that is only here in the great Commonwealth of Mass.

    Others will give you feed back for their sections of the country and world.

    E4 Jack

    MA National Guard
  • Weezbo
    Weezbo Member Posts: 6,232
    Mor L

    i use both...M mostly L for looks or where freezing on a "down" system might be a bit of a bad itch to get back into.L is able to take more freezings. 80 K for under grounds ,yellow for DWV,then there are special pipes used in science experimentations where electrical wire doesnt get it.
    STEVEN MARKS Member Posts: 154

    M for heat
    L for domestic water
    A lot of companies only use L so that plumbers dont mistakenly use M on water lines
  • Brad White_2
    Brad White_2 Member Posts: 188
    Call me conservative

    but I use L on all FHW and domestic water piping both installed in my house and as a specifying engineer. Type M just has that thin feel to it and can kink and dent if you are threading it into a tight space. Subjective I know. But once bought, it goes forever. Just MHO...
  • ScottMP
    ScottMP Member Posts: 5,884

    Twenty Five years in the trade and I have never used anything but M on Hydronics. Never a problem.

    We did go thru a problem where some contractors were using M for water piping and it pitted right thru after about ten years. Massachusettes code is now L only for domestic water, but we still use M on heating systems. Allthough now its more pex-al-pex than anything.


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