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Slant/Fin boiler head loss?

ARCJ
ARCJ Member Posts: 2
in THE MAIN WALL
Hi All,
I've been searching the web for a head loss on a Slant/Fin Sentry boiler with no luck and Slant/Fin doesn't post a customer contact phone number. The closest I could come was a part number for the circulator, but couldn't find a pump curve for that either.
Is there a rule of thumb I can use to estimate what the boiler head loss might be, or is it too variable between manufactures? The model is S-90 with 76,000 btu/h output so I'm targeting 7.5 to 8 gpm.
Thanks!

Comments

  • hot_rod
    hot_rod Member Posts: 22,703
    If it is a cast iron sectional, very little pressure drop. Its a cast iron kettle

    The control does  have some return protection function, if you have a high mass system
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • ARCJ
    ARCJ Member Posts: 2
    Awesome, thanks for the quick reply Bob! Greatly appreciated.
  • HomerJSmith
    HomerJSmith Member Posts: 2,549
    edited August 2023
    Cast Iron boilers head loss are most likely in the range of 1/2 to 3/4 'hd. Very low.
    I expect that the pump is a Taco 007, so look at that pump curve.

  • HomerJSmith
    HomerJSmith Member Posts: 2,549
    edited August 2023
    I don't know your sys. How you plan to pipe it. Know that a flow of 8 GPM requires a larger pipe size for a connection to the boiler and any manifold. A larger pipe would lower the head loss and the rate of flow. Stay within the limits of GPM for any pipe size to prevent noise and pipe erosion. Different piping materials have different GPM limits, steel, copper, pex, etc.
    Look, if you have 8 GPM leaving the boiler you have to have 8 GPM coming back into the boiler. If you have 4 balanced zones. each zone can carry 2 GPM. But, there may be times that you may only have one zone open and you are trying to squeeze 8 GPM thru it, Think about an ECM pump that changes revolutions and GPM flows as is needed.

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