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Pipe head loss calculation - advice wanted

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  • Pipe head loss calculation - advice wanted

    I am designing a radiant heat installation whereby a hot water travels approx 80ft to / from a manifold in copper tubing, and need help with the head loss estimate. (for purposes of this discussion we can ignore the head situation in individual loops as there will be either a large heat exchnager with a separate pump in the secondary loop, or pumps in the loops)

    The heater (Takagi TK-3) introduces approx. 15 ft of head-loss. There will be a couple of swing type check valves in the flow, plus about 10 90 deg elbows, all sweat-type. I can use long-turn elbows if that helps.

    The pump, Taco 009, can handle approx. 22 ft of head at the designed flow rate of 4.5 GPM.

    The online head calculators I've tried, give me widely different estimates between 7 and 15 ft of head loss for 3/4" copper piping.

    I can switch to 1" piping or even 1.25", but not sure how much head loss it will save given 4.5gpm flow rate.

    Would appreciate any insight or advice here.

    Thanks

    Alex

  • #2
    Re: Pipe head loss calculation - advice wanted

    Originally posted by AlexK View Post
    I am designing a radiant heat installation whereby a hot water travels approx 80ft to / from a manifold in copper tubing, and need help with the head loss estimate. (for purposes of this discussion we can ignore the head situation in individual loops as there will be either a large heat exchnager with a separate pump in the secondary loop, or pumps in the loops)

    The heater (Takagi TK-3) introduces approx. 15 ft of head-loss. There will be a couple of swing type check valves in the flow, plus about 10 90 deg elbows, all sweat-type. I can use long-turn elbows if that helps.

    The pump, Taco 009, can handle approx. 22 ft of head at the designed flow rate of 4.5 GPM.

    The online head calculators I've tried, give me widely different estimates between 7 and 15 ft of head loss for 3/4" copper piping.

    I can switch to 1" piping or even 1.25", but not sure how much head loss it will save given 4.5gpm flow rate.

    Would appreciate any insight or advice here.

    Thanks

    Alex
    Sounds like you shot off your mouth on designing a system you're not qualified to design. Now someone on this forum is expected to design it for you.

    Good Luck.
    the dog

    Comment


    • #3
      Re: Pipe head loss calculation - advice wanted

      Originally posted by plumbdog10 View Post
      Sounds like you shot off your mouth on designing a system you're not qualified to design. Now someone on this forum is expected to design it for you.

      Good Luck.
      Do you mean head loss (due to height) or friction loss.

      Comment


      • #4
        Re: Pipe head loss calculation - advice wanted

        sounds like he means friction loss of 3/4 copper.

        AlexK needs to get his hands on a copy of Crane Technical Paper 410

        the link will take him there.

        Comment


        • #5
          Re: Pipe head loss calculation - advice wanted

          Thanks Franklie. Much appreciated and constructive. I am also getting the Wirsbo design manual.
          I am talking about total dynamic head but given the length needed and since the setup is largely horizontal the friction loss is a big part.



          The dog: you are right in that my client has a fool for a plumber, but since the client is me, I see nothing wrong with the situation.

          Seeing the "work" of the plumber in our area, I'm sure I can do even worse, but given my stubbornness, it will take actually me trying and failing to prove to myself that I am incapable of doing better. :-)

          Comment

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