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Integrated flow control

vspa5007
vspa5007 Member Posts: 4
in Radiant Heating
When do I need a pump with IFC? When it is pumping up to the second floor? I computed I need a 20' head pump with around 1gpm to get to my 2nd floor bathroom. Do need the IFC options?

Comments

  • Ironman
    Ironman Member Posts: 7,510
    Flow Checks...

    Are needed when there are multiple circs. in a system to prevent hot water from being pumped into a parallel circuit that is not calling for heat.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • vspa5007
    vspa5007 Member Posts: 4
    IFC

    Thanks for the quick answer
  • Ironman
    Ironman Member Posts: 7,510
    My Pleasure

    .
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    There seem to be two kinds of flow check valves.

    One type of flow check valve is a spring-loaded valve, such as those built into some circulators, such as the Taco 007-IFC. The spring is relatively weak so as not to introduce too much head in the circuit.



    http://www.taco-hvac.com/en/products/Wet+Rotor+Circulators/track_file.html?file_to_download_id=10683



    If you are supplying two zones from a common supply and return system, the IFC valve will prevent reverse flow through an unpowered circulator. It should be pretty obvious why you would not want the reverse flow.



    The other type of flow check valve has a weighted plug that closes off circulation unless sufficient forward pressure is exerted to open it. A valve like this will prevent reverse flow just as the spring-loaded valve does. But it also will prevent forward flow as caused by temperature differences. This is sometimes called ghost flow because at is caused by the differences in specific gravity of the water at different temperatures. It can even flow in both directions at once in relatively large diameter pipes. There are different ways of getting around this problem, but a flow check valve, such as this one:



    http://www.taco-hvac.com/en/products/Zone%20and%20Flow%20Control%20Valves/track_file.html?file_to_download_id=15472



    will certainly work.



    I have three circulators in my system that are IFC types, and one FlowCheck valve to keep ghost flow from occurring.
  • Gordan
    Gordan Member Posts: 891
    As demonstrated by your setup...

    A spring check will prevent ghost flow just fine. You just need one (or a weighted flow check) on each side of a branch circuit, so the ghost flow does not go up the return riser.



    It's the third kind of check valve, one that has a hinged "flap", that is generally unable to stop forward ghost flow.
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