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Primary/secondary piping

mike chacon
mike chacon Member Posts: 17
in THE MAIN WALL
On primary loop which includes my cast iron boiler, does position of primary pump matter if positioned before closely spaced T's (secondary loop) or downstream/after closely space T's ( primary pump >>>>>>>>Thanks mc

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,852
    Doesn't matter Mike

    So long as all pumps are pumping away from the expansion tank.



    ME

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  • mike chacon
    mike chacon Member Posts: 17
    Primary / secondary

    The primary pump will be pumping away from expansion tank, the secondary pump I guess will be pumping away. Will the additional head from primary pump passing the closely spaced T's cause any issues with secondary flow. My desire is to have slightly more flow through primary/boiler loop to help boiler return water to come up/rise in temperature faster to help with boiler protection before majority of heat sucked away to secondary heavy radiator loop.
  • mike chacon
    mike chacon Member Posts: 17
    Hey ME

    How's the mountain house/flying saucer. Everything up/ working. Saw post on TV episode. Missed the show, hope I can see repeat on Comcast "On Demand.

    Mc
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Nope

    If piped correctly, both loops will be isolated from each other.  The head in each loop is a function of pipe size & length, and the circ on that loop.  On the boiler loop, plus loss thru the boiler

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,852
    Still doesn't matter...

    Mike, The inlet to the secondary pump may see the higher discharge pressure from the primary pump, but the primary pump will still not induce flow through the secondary. For example, if the primary is capable of generating 10 PSI of pressure, and the secondary pump can only generate 5 PSI of pressure, then the secondary pump with a static fill of 12 PSI will see an inlet pressure of 22 PSI, but it (the secondary) can still only add 5 PSI, so its discharge would be 27 PSI.



    Make sure that you have the proper amounts of straight pipe before and after secondary connections.



    The Space Ship is moving along slowly. Waiting for the electricians to get done with their work so I can finish mine :-)



    ME

    There was an error rendering this rich post.

  • Ben Greenfield
    Ben Greenfield Member Posts: 25
    Where are the magic formulas for pipe spacing?

    Hey all,



    I'm working on a longer post regarding primary secondary piping but I thought I would tack a basic question on this topic.



    Is the proper spacing for piping from the primary circuit each supply tee has to be within 12" of the previous supply tee but not closer then 5".



    Returns don't matter.



    Are there other details to keep in mind?



    Thanks,



    Ben
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