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LLH odd question....

kcopp
kcopp Member Posts: 3,717
edited August 2015 in THE MAIN WALL
I will pose this question even though it may be a dumb one. Is there any reason why is piping a LLH that you cant run the supply in through the bottom of the device and return out the top side?

Comments

  • Steamhead
    Steamhead Member Posts: 14,462
    There is no such thing as a dumb question.

    But someone else is going to have to answer this one....................
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    jonny88
  • RobG
    RobG Member Posts: 1,850
    The only reason that I can see is that the hot water is going to want to migrate up? I have always wondered why the boiler side and the system side aren't staggered to mix the water. I guess I just don't understand fluid dynamics.
  • hot_rod
    hot_rod Member Posts: 14,785
    Sure you could. Typically you want to use the LLH as a multifunction device, more bang for your bucks.

    \The air removal vent is at top, so you want the warmest water at the air removal portion. Dirt removal at the bottom where the drain cock is. Catching dirt and debris as it returns from the system before it can get into the boiler, pumps, etc.

    Assuming that you are using a LLH that has the media inside to increase the function and performance?

    Better yet get a 4 in 1 device Air, dirt, hydraulic separation, and magnetic separation.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • RobG
    RobG Member Posts: 1,850
    But why do you go in and out of the same side instead of staggering them? I always perceived them as a small buffer tank. hydraulically separating as well as mixing.
  • hot_rod
    hot_rod Member Posts: 14,785
    yes they could be staggered. In the case where both input and output are exactly the same gpm (rarely) the flow is straight across, no mixing or separation is taking place.

    Staggering them would possibly allow more buffering, but very little in a sep that holds 3 gallons.

    True buffer tanks, like the ones built for chillers, have baffle plates built in to force the flow through the entire tank.

    It's a bit tricky building a tank to serve as both a separator and buffer, especially with varying flows. Separation is easy, but getting the whole capacity involved as a buffer, not as easy. If both in and out flows are identical not much mixing in the tank, same as a separator. In the off load cycle you would start buffering some.

    I like the two pipe buffer tank concept better IF you plan on a lot of different flow rates. The separation function actually takes place outside the tank in a big wide spot in the interconnection piping. The tank has a better "at bat" for buffering.

    Once you build a buffer tank to also act as a separator however, you would not want a baffle inside. So it really comes down to what you are trying to accomplish. The separator was intended to be a step or two above closely spaced tees, offering that separation but adding more features and benefits.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    RobGzavnetkcopp
  • kcopp
    kcopp Member Posts: 3,717
    Well that is helpful.
    I have been looking for a good source of welded SS screening... say 1/4" that I can wrap and place in side of the LLH that I have had welded up. (ty Lee @ Earthlee). I have used perforated copper in the past, and have thought about getting a spirovent replacement core, but screening is what I really want.
    Any leads?
  • hot_rod
    hot_rod Member Posts: 14,785
    Is it all welded up with removable top or bottom? if so a composite media could be installed.

    If you need to weld on the piece with media inside you want stainless. Stainless seems to be the best choice, it holds up well to all types of fluid conditions.

    How much do you need, I might has some misc pieces.

    McNichols is where you can source all sorts of speciality mesh and expanded metals, they have locations across the US.
    I've been to the one in Chicago area, they allow walk-ins, they cut and fab there also, great selection of unusual metals.

    www.mcnichols.com
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    RobG
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