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monoflow system base board

mtfallsmikey Member Posts: 765
Used to bleed with fill pressure ONLY at first. Then start boiler/circ(s). With radiators it would usually go on the first try, BB was always a return vist.


  • ed m
    ed m Member Posts: 65
    b.b monoflow system

    installed a 10 ft section of copper baseboard in kitchen remodel moved monoflo tee in basement further down the line on the return side to componsate baseboard, put 90 bleeder on return side of baseboard and not getting any flow, bleed it out getting water but no flow, so i decided to put monoflow tee on the supply side too, to make the water want to flow through b.b. still no flow.
    i am gonna try to but a ball valve and boiler drain on return side tee in order to make sure its not air bound. any suggestions? tees are in the right way checked them 10 times. thanks for the help
  • Bruce M_2
    Bruce M_2 Member Posts: 123

    What is the size of the baseboard line? Is it 3/4"? What is the size of the main line? There are formulas for computing the size of the piping (usually 1" and larger (1-1/4" used to be a very common size). The monoflo is on the return and if the baseboard is above the main line it should be installed at a 45 degree angle facing upwards.
  • Tony_23
    Tony_23 Member Posts: 1,033

    Which style, or brand, are the tees ? Orifice or scoop ? Orifice tees with a cone need the cones pointing opposite each other. The cone points towards the supply on the supply, and the return tee needs to have its cone pointing downstream to create a venturi action.

    Did you bleed w/o the circ running ? Sometimes with the circ running it'll pull the air bubble down just enough that it won't bleed.

    Pipe sizing is irrelevant to your scenario.
  • Steve Minnich_3
    Steve Minnich_3 Member Posts: 42
    bleeding monoflo systems

    Conventional wisdom says that when you get water, stop bleeding. In my experience with monoflo systems, that wisdom doesn't hold true. Depending on how large the systems is, you may need to "re-bleed" each one 2-3 times over the course of an hour or so.

    I had one just two days ago where I bled everything thoroughly after the repairs were finished. Turned the burner and pump on, and needed to do it all over again twice before everything heated evenly and consistently. Each time, getting a considerable amount of air out after having just water initially. When you think about the way it's piped, it's easy to see how that can happen.

  • what matters here is path of least resistance. The water is finding it easier to flow through the main.
    If you're not getting air, stop bleeding.
    Add a second monoflow tee. equally spaced them as wide as the baseboard. If you can't do that, then make the baseboard part of the main or add another zone.
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