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home run system pump selection?

steve_109
steve_109 Member Posts: 2
in THE MAIN WALL
Already have one included in the order!!!!!!

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  • steve_109
    steve_109 Member Posts: 2


    When selecting a pump in a 6 branch home run panel rad system, is the pump sized for the highest flow and highest head branch?? I think my highest flow is .66 gpm and am using 3/8" PAP. I also have a manifold with flow setters (probably overkill since I have TRV's).Thanks!
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Yes, highest through the piping is the longest (presuming all piping the same size) branch.

    But, you ALSO include the pressure drop of the TRV! You should have a decent idea of flow for each panel at/near design conditions. Find the TRV restriction (all mfgrs. should supply tables) for that flow and add to the piping loss for that branch.

    The longest run [might] not have the highest restriction... It will also depend on the flow through the TRV.

    Personally, I'd adjust the flow setters for wide open and let the TRVs do their job. If you really want to split hairs compute the total head loss (piping + TRV) for each panel. For the highest head loss found leave the flow setter wide open. Adjust the others down to compensate for lower head loss. The TRV-like FHVs (floor heat valves) have this adjustment built-in with the scale based on head loss, not flow amount.
  • J.C.A._3
    J.C.A._3 Member Posts: 2,980
    Pressure differential bypass valve....

    There are some nice, and adjustable ones available. Check into it.

    As TRV'S close, the pump can just dump its load back to the return of the system, keeping the pressure constant in the feed loop. Chris
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