Differences between suction side piping configurations

nottinbe

Gold Supporter
Jun 2, 2016
14
Webster Groves, MO
#1
Hi all,

As I watch my pool turn from green to really dark green I'm finally ready to start getting my equipment pad put back together. While laying out the valves for the suction side I started wondering if there would be any difference in flow between my three pipes based on how the pipes were T'd together.

Would this configuration pull more water through pipe A since it is a straight shot to the pump? If so, would B be second in flow and C 3rd? Something else?
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Would this configuration pull more water through B and less but equal through A\C?
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Or does it not matter at all and (assuming identical runs of pipe) flow would be the same through A, B, and C regardless of how it was piped?

Thanks!
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#2
Any difference in flow would be negligible because the head loss in an individual pipe getting more flow will increase thus making the water more likely to be pulled from the other pipes.
 

CJadamec

TFP Expert
Apr 29, 2016
2,194
Quaker Hill, CT
#4
As was already said it doesn't really make a difference which way it is plumbed. If you really want to make it fine tune the skimmers a ball valve on each line right before they tee together will allow you to adjust or isolate skimmers in the future. And if you use union ball valves it's a hand place to access the skimmer lines if the become clogged or to winterize.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
10,488
Bedford, TX
#5
Not,

I assume that you plan to make all those "T's" 3-way Jandy valves and not just leave them T's???

How far (roughly) are the three devices?

Jim R.
 
#6
Or does it not matter at all and (assuming identical runs of pipe) flow would be the same through A, B, and C regardless of how it was piped
Hello and Welcome to the Forum.

in your post, last line, you asked us to make an assumption that all runs were identical. If that is the case, then yes the 3 pipe runs would basically be the same, except for a straight, tee, and elbow where they all come together. These all have about the same relative head loss at low velocities, so I doubt you would notice any difference.

But, and this is a big BUT, we have to step back into real life. I doubt your runs are identical except for these three bends. the far side suction, skimmer, bottom drain, would all have different lengths, distance and vertical heights and thus different head values. This would probably lead to somewhat different flows in each, but again it isn't the 3 bends that make up the manifold causing the difference.

Usually there are valves in each pipe right before the manifold so that you can adjust the flow rates from each source. The adjustment isn't to make the flows the same, but to balance out your system as needed. I think you will be glad you added the valves later on.

[edit] sorry for the double posts, apparently I type slower than the others, lol [/edit].
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#7
I agree with CJ, you really should be putting valves so that you have control over where the water is drawn from. I would not however suggest the use of ball valves and instead would suggest getting pool valves like the Neverlube. You could do it with 3 2-way valves or 2 3-way valves or 1 of each depending on how you want the control.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#9
The ball valves tend to get stiff until you either can not turn them or the handle breaks off. Then you have to redo the plumbing. Pool valves do not have the stiffening problem and are rebuildable without having to redo any plumbing.

Granted this may only be important for valves that you actually are going to be changing fairly regularly. In this situation, likely once the valves are set they will not usually be changed ... until they want to isolate suction from just the floor or something and then try to move the valve and it breaks ;)
 

nottinbe

Gold Supporter
Jun 2, 2016
14
Webster Groves, MO
#10
I'm definitely a fan of valves and unions. The lack thereof is a big reason I'm redoing this whole thing.

I have 3 2-way Jandy Neverlube's ready to go, one for each suction line. I was planning to put union's on the pool side of them just above waterline. I was considering a 4th 2-way before the pump (on the single merged suction line) to make it easy to shutoff when I have to open the pump as my pump will sit slightly below waterline. I'm going to see how annoyed I get with closing all 3 each time. It will be easy enough to add the valve later given the unions before the valves and unions at the pump.