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figuring out the feet of head that a pump must work at

Ken_40
Ken_40 Member Posts: 1,320
in THE MAIN WALL
A grammarian trapped in a man's body; even if that body is Brad's.

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  • Walt_5
    Walt_5 Member Posts: 14


    can someone please tell me the formula for figuring out what my feet of head of the pump should be, I measured and calculated equivalent length , it is 258', this is the longest loop on a 4 zone 3/4 baseboard loop. The baseboard btu/hr comes to 127,956.
  • Ken_40
    Ken_40 Member Posts: 1,320
    Need one more refinement please.

    You state the load is 127,956 BTU's. One must assume that is the total load for all four zones, right? Or does the one single 258' loop/zone alone have 127,956 of load?

    The BTU load of the longest loop is required to make the calculation. There is a formula I assume, but there are tons of B&G Syzer type devices and I=B=R tables that already have the answers, we rarely use the formula, just the simple tables.

    If the one 258' zone has a 127,956 BTU load, and a 20 degree dT is what you're loking for, you'll need a circulator with a capacity of 13 GPM at 111 feet of head. That can't be right. What's the load just for the longest zone?
  • Brad White
    Brad White Member Posts: 2,399
    Ending sentences with prepositions

    is something about which we will not put.

    :)
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
  • Brad White
    Brad White Member Posts: 2,399
    The quote

    was originally from Winston Churchill, poking fun at the notion of grammarians in general, Ken.

    The correct response would have been what the new full basketball scholarship freshman at Princeton said.

    He had asked an upper classsman, "Yo, Bro- Can you tell me where the library is at?"

    The Upper Classman said condescendingly, "At Princeton, we do NOT end our sentences with prepostitions..."

    "OK then. Can you tell me where the library is at, A**hole?"

    :)
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
  • Glenn Sossin_2
    Glenn Sossin_2 Member Posts: 592
    curious

    Understand / agree with the 13gpm, but how did you arrive at 111 ft of head?
  • Ken_40
    Ken_40 Member Posts: 1,320
    Until he gets us more info...

    I assumed (knowing it was extremely unlikely)the entire load was the one zone's output. I was just having fun with it.

    I used my old handy B&G System Syzer. That many BTU's at that dT was actually off the table! I had to extrapolate outside the window to even get the 111 estimate.

    I'm certain the load is split between the 4 zones he states are present, if not, the lights in his entire neighborhood will dim when the circulator starts (;-o) Especially with 111-feet of head. The draw may be in the 200 amp range (;-o)
  • Jeff Elston
    Jeff Elston Member Posts: 289
    pump

    One of many calculations you can make would be to assume that there is 4 FT of head per 100' of pipe.
    So At 285' you will have a head of 11.4' in 3/4 copper

    So I multiplied 285 by .04 this comes to 11.4




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  • Ed_26
    Ed_26 Member Posts: 284
    Grammer

    Are you sure that's not "grammatician"?
  • S Ebels
    S Ebels Member Posts: 2,322
    I think.........

    He used to kick field goals for the Patriots and now works with Peyton Mannings crew in Indy. ;)
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