Pool Opening Problems.

[TheGoose]

So do you agree with my assessment that I have about ~50 ft of head on the pump and it's probably close to what the pump curve is?

[PoolDoc]

I haven't really checked -- I was just taking what you and Mark said, at face value.

For me to be comfortable estimating your TDH (total dynamic head), I'd want pictures of you skimmer(s), return(s), all equipment connections, pump, filter, valves & piping.

[mas985]

Return head is a know quantity from the filter pressure, ~49' of head. The only unknown is the suction head but as I posted before, that should be minimal because of the dual suction lines. I wouldn't expect more than a couple feet of head IF both lines are kept open all the time. If you want confirmation, I would need more details on the suction lines (diameters, lengths), number suction side valves, and the height of the pump above the pool water level. I can pretty guess the rest and get within 5%.

[PoolDoc]

My bad; should have scanned back for the pictures.

Using the Hazen-Williams calculator here, for the pipe between the pump and the filter (3xL; 1x branchT; 8' pipe => 20' equivalent length), I get a head loss of 9ft at 80gpm and 11ft at 90gpm. Using the Hayward chart I sent you, Mark, I calculate the drop through the dumb-head Tee layout as 3.5ft at 80 gpm and 4ft at 90 gpm. Estimating the equivalents lengths of the 1.5" piping to the pool at 50ft, and splitting flows evenly at 40gpm each and 45gpm each, I find a loss of 6 ft at 80gpm and 8ft at 90gpm

Taking filter pressure at 49ft, I estimate TDH around 57.5 ft @ 80 gpm(9+3.5+6=18.5) and 62 ft @ 90 gpm (11+4+8=23).

also used Charlotte Plastics Design manual

[Watermom]

Aren't you guys thankful for your math teachers!

[PoolDoc]

Honestly, I didn't learn to USE math until I was (a) taking engineering classes and (b) simultaneously doing repair work and realizing that I could use some of what I was learning in class to make my work easier.

[Watermom]

understand of how to use math in their daily lives.

That is something I talk about with my students every day. There is no reason to learn math unless you have a use for it. (Of course, some of my smarty-pants kids say then that they shouldn't have to learn it because they have no use for it!) Some day ..........

EDIT --- Rereading that it sounds backwards of what I was trying to imply but you guys know what I mean. My excuse for lack of clarity is that my mind is not on what I was writing right now cuz we are off to Baskin Robbins to get an ice cream cone!