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"twin tees" as an alternative to closely spaced tees?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by pybyr, Aug 3, 2008.

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  1. pybyr

    pybyr Minister of Fire

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    are any of you familiar with TACO “twin tees”:

    http://www.taco-hvac.com/en/products/LoadMatch<sup>®<_sup>+Twin-Tee<sup>®<_sup>+Fittings/products.html?current_category=118
    and
    http://www.taco-hvac.com/en/products/LoadMatch<sup>®<_sup>+Twin-Tee<sup>®<_sup>+Fittings/track_file.html?file_to_download_id=15084

    they look like an ingenious way to achieve the same effect as “closely spaced tees” only with less horizontal real estate in & occupied by the primary loop.

    They appear to have been on the market for at least a few years, but I find surprisingly little about them (not even finding on-line sales listings or pricings) on the 'net

    Anyone aware of any drawbacks?

    thanks

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  2. Donl

    Donl Feeling the Heat

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    The twin tees would not be a replacement for closely spaced tees. Closely spaced tees should be a couple of pipe diameters from each other, one up steam from the other, not directly beside each other.
  3. pybyr

    pybyr Minister of Fire

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    Don- Taco specifically describes these in their literature as a substitute for closely spaced tees

    Generally, as I understand it as a newcoming bumbler to hydronics, the goal is to have tees as close as possible, so that the deliberately-controlled secondary circulator flow, not any differential head between tees, drives the flow in the secondary circuit; this does it one better by having the tees side by side.

    If I'm missing something, what am I missing?

    Hot Rod, I'd be _most_ interested in your "take" on these twin tees, even though I know they're from a different co. than the one you're working most closely with (and I'm really finding the "Idronics" pieces useful, and leaning towards the Caleffi dirt separators)

    best regards, all
  4. Donl

    Donl Feeling the Heat

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    Trevor

    From my understanding of closely spaced tees, I don't see how the twin tees could provide the same effect. I'm trying to picture the flow in my head, and the twin tees just don't work for me. I am no expert so I will wait until someone with more knowledge in this regard chimes in. If my understanding is flawed, then I hope to learn something.
  5. Sting

    Sting Feeling the Heat

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    This design from Taco takes all the work (design expertise) out of a close spaced tee application and ANYONE can pipe a P/S system correctly!
  6. Donl

    Donl Feeling the Heat

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    Having taken a closer look at the documentation I can now see how this works. I was having trouble visualizing the flow. It seemed to me that the return flow could easily mix with the supply flow. I now see that an internal baffle is used to prevent this. Hey! I learned something.
  7. pybyr

    pybyr Minister of Fire

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    Sting & all - there's lots of other things I have developed expertise in, and when it comes to planning the P/S loop of my wood boiler to my water/air coil, future DHW, and future radiant, I WANNA be a dummy- but a dumb and happy dummy who gets good results the first time and doesn't have to do it over.

    While I'm aspiring to be dumb and happy (at least after I get done with my wrenches, propane torch, and Wirsbo expander) I invite suggestions on pipe and tee sizing for the secondary of a 150kbtu wood boiler to the primary, the primary itself, and the secondary from the primary to an air coil in the ductwork above my bulletproof but now economically prohibitive ThermoPride 125kbtu oil hot air furnace with a 22x22 outllet leading into 8x24 ducts.
  8. in hot water

    in hot water New Member

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    I have yet to try the Taco twins, but I understand they are a replacement for closely spaced tees. A nice clean look, also. I have seen a similar device in Germany made by Braunash) It had multiple taps off a cast brass manifold with that divider down the center. Great looking design.

    They also have some interesting primary/ secondary steel manifolds. Here is their colorful booth at the Frankfurt ISH show a year back. A fellow up Wisconsin way imports some of their stuff. Known by "radiant Ted"

    hr

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  9. deerefanatic

    deerefanatic Minister of Fire

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    II thought of going with the twin-tee system... But it was very cost prohibitive compared to just using black iron fittings and nipples......
  10. pybyr

    pybyr Minister of Fire

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    I was able to get a further response from Taco, which actually came from their Greg Cunniff, a professional engineer, and their Applications guru-- excerpted here, below, in part, with one of several photos he supplied confirming that the Twin-Tees allow the Tees to be placed right up against one another, and also right near elbows or other fittings (which you can't do with the close-spaced separate tees as are the common way to do primary-secondary)

    This is encouraging news for folks like me who may want to do a moderately complex primary-secondary arrangement without taking up huge amounts of physical space

    begin quote from Taco:

    "John Siegenthaler's comments about turbulence from closely spaced tees in a
    primary-secondary configuration are industry recommendations to minimize turbulence,
    head loss and possible oerational problems.

    We mitigate turbulence in our takeoff tees in a primary-secondary configuration with
    the baffle in our Twin Tee. We have systems installed with the tees shoulder to
    shoulder. We have also installed Twin Tees immediately upstream and downstream of
    elbows. In all cases there have been no operational problems.

    See the attached pictures from Two Bear Ranch in Whitefish, MT. This is a 30,000
    sq. ft. residence. There have been no operational problems. In fact there have
    been no problems.

    We recommend that the center to center spacing between side ports or takeoffs of
    tees be as close to zero as possible. That is why the takeoffs on our Twin Tee are
    perpendicular to the flow. The spacing between these takeoffs in direction of flow
    is zero. Any additional distance between side ports or tees increases the risk of
    ghost flows from differential pressure between the tees. We have seen pressure
    differentials of 3" to 5" w.c. between side ports or takeoffs with only 4 to 6 pipe
    diameters. "

    <end quote from Taco>

    See also the photo Taco provided showing a couple of Twin Tees right up against each other, and right near an elbow.

    I have no affiliation at all with Taco- just find this to be a potentially really handy product, and am pleased with Taco's willingness to comprehensively confirm that if I use it, I won't need to worry about the usual spacing recommended in the trade for distances between pairs of close-spaced tees and anything else upstream or downstream

    Attached Files:

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