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Grunfos Alpha

Typical old hydronic system, 1.5 inch steel pipe through basement with cast iron radiators.. A Runtal is installed with poor flow in the kitchen of 1/2 copper lines, as we know there is a lot of options-  if a Grunfos Alpha is installed on the 1/2 copper lines & plugged in to a regular outlet will it sense flow when the main zone kicks in and happily pump more flow to the Runtal radiator?  My thought is that it won't get the jolt it needs to kick in...


  • Zman
    Zman Member Posts: 7,447

    I have had the problem you describe with an alpha with 1/2" tubing in auto adapt mode. It is worse with the check valve installed. The problem goes away in constant pressure mode, that's not really what you are looking for.

    The alpha is a pretty expensive solution. Could you wire a smaller circ into the zone control and call it good.

    An alpha has low energy use when not pumping, it still uses a few watts.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • SWEI
    SWEI Member Posts: 7,356
    One zone pump

    Try a B&G ecocirc e3 Vario.  Dial in the flow and let 'er rip at
  • gennady
    gennady Member Posts: 839

    Very good circulator. just calculate head for the zone and look up head - flow diagram for proper settings. it will stop when zone valve closes, but buy circulator with internal flow check valve.
  • Paul Pollets
    Paul Pollets Member Posts: 3,620
    Pumping Away

    It's unusual that the Runtal has reduced flow. I'd be looking at why, rather than adding an extra pump. Since the Runtal was added long after the original radiators were piped, the connection to the original mains might be backwards or the near boiler piping is not set up for "pumping away" on the supply header from the expansion tank location. This presumes that the Runtal rad is rated less than 10K btus since 1/2" piping is connected.
  • Ifollowinstructions
    Ifollowinstructions Member Posts: 27
    50 years later!

    You have been reading to many books- a old forced hot water cast iron radiator system will happily work with the pump installed backwards or even if its burned out. . Pumping away is more for baseboard as the air gets in and creates problems.

    90% of boilers are installed wrong! why? Mr home owner with his education assumes we are all the same...it says plumber on the side of his truck-

    As no one seems to have a clue, I nominate myself as president of the no nonsense club- keeping it real.

    First question I ask a home owner with a heating problem, has modern man been here screwing it up?  He just left Home Depot with a garden hose,
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited August 2013
    A Wise Man

    Once said, water is dumb, lazy, why would it want go there no matter forward or backward?

    Hmm. What's a typical old hydronic system? Didn't know there was one. Mono flow? Old gravity steam system converted? Your looking for an answer with little information brought to the table.

    To answer your question about the Alpha. Sure it will, its a pump, plug it in, impeller moves and presto, so does the water. PS. A circulator pump will move water 200 years in the future too.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • EricAune
    EricAune Member Posts: 432
    Books are useful, try one.

    Paul and Chris have both covered the areas of concern here. And pumping away has so much more to do with pump performance through a system than air problems. Click the "Shop" tab above and buy Dan's book. You might be surprised how helpful it is. 
    "If you don't like change, your going to like irrelevance even less"
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,840
    Nice job of offending your teachers...

    Not a good way to get information.

    Just because you don't understand physics, you condemn the people who are giving you good and proven information?

    Your question was properly and correctly answered, and you saw fit to verbally offend them?

    Don't expect to get many more answers from qualified experts like Paul Pollets from this venue...
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Ifollowinstructions
    Ifollowinstructions Member Posts: 27
    Dan's Books--

    Yes I have read all Dan's books-- He believes in thinking outside the box and finds humor in his world.    Some of us actually create whats in the books that you guys read about...We might not spell correctly but you know what! We show up & never run away....

    My original question was not answered- I wish you well, maybe we should talk about you're favorite movie.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited August 2013
    Your Original Question

    Was answered. You haven't brought enough information to the table other then your wise and disrespectful mouth. Why don't you take five minutes and sketch out a diagram and post it. While your at it let us know how many btu/hr you need to deliver to that rad and its size. Even though your a ****, you'll still get some help.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Zman
    Zman Member Posts: 7,447
    I misread th OP....

    No the Alpha will not sense the flow in the main pipe and kick in. It does not work that way.

    See, question answered. I think some folks on here got the crazy idea you were looking for the best solution for your problem, not the answer to a specific question.

    Question answered.

    You're  welcome.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
This discussion has been closed.