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Sizing pump for Indirect

Rob_34
Rob_34 Member Posts: 21
in THE MAIN WALL
On a previous post with pictures of a Weil McLain install there were comments on the size of the circulator for the indirect. I was going to install a Bradford White Power Core 80 gallon and wanted to know what size cirulator I would need. I always thought that head pressures were low in the indirects.

Rob

Comments

  • ALH_4
    ALH_4 Member Posts: 1,790
    Head loss

    That particular indirect, with the fittings in the top of the tank, has extremely high head loss. I would recommend a 26-99 on that tank to maximize performance. The coil is long and small diameter.

    -Andrew
  • Floyd
    Floyd Member Posts: 429
    All indirects are not created equal...

    as was stated this indirect needs a high head pump and may not even work with some Mod/Con unit combinations, because you simply cannot drive enough water through that coil....
    Even with basic boilers, flow is directly linked to the amount of hot water that can be made by the indirect.....

    Floyd
  • hot_rod
    hot_rod Member Posts: 23,405
    BW has redesigned their

    indirects. I'm not sure what vintage you have, but the new ones are 1-1/4" coils. Also with the updated CombiCor. Large diameter enamaled steel coils.

    The older ones had a 5/8" diameter looooong coil. Quite a bit of pressure drop, although I have flowed them with a 15-42. Just takes a while to recover :)

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
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