Plumbing and Hydraulics Review requested.

[Fastcarr]

New build on-going and new member.. So glad I ran across TFP when doing research. Routinely the best info! Amazed at how much money is being spent by pool owners on pools based on “rule of thumb” or “that should work mentality”.

Reaching out for review of our plumbing and hydraulic calc’s.

Attached is a diagram of the piping layout. Not pictured is optional home runs for the water features (3 bubblers in the tanning ledge) and home runs for 6 deck jets. The diagram has the bubblers being supplied by a symmetrical loop and 6 deck jets are supplied with a serial loop.

Considering Pentair eqpt and automation—two variable speed pumps, quad de filter, uv sanitizer, automation, heater (perhaps Hydra Royal 137,000 btu).

Smmary of the system.

Suction Side:

• 2" Discharge 32" Trench Drain
  • All three ports available for return / suction
  • Actuator valve to split return load to top and bottom returns (advice pls)
• 2 Quikskim Venturi Skimmers
  • Multiline or home runs to each

Return Side:

• Top return Loop: 4 returns supplied with a serial loop
  • Would like to run the V-Fitting Venturi Control
  • Actuator Valve
    • close / open top return loop to concentrate heated water to bottom return loop
    • perhaps to increase velocity of return to bottom for periodic cleaning
• Bottom return loop: 4 returns supplied with a serial loop
  • Would like to run the V-Fitting Venturi Control
  • Actuator Valve
    • close / open top return loop to concentrate heated water to bottom return loop
    • perhaps to increase velocity of return to top for periodic cleaning
• 2 Quikskim Venturi Skimmers
  • Actuator Valve to control flow to skimmers during cleaning (Advice pls)
• Water Features
  • 3 bubblers with symmetrical loop
    • Will we need independent adjusting valves (manual)?
    • Actuator Valve
  • 6 deck jets
    • Alternative piping depending on desired head loss and velocity
      • Serial Loop
        • Will have individual adjusting valves
      • Home Runs
        • Will have individual adjusting valves
          • Home Runs with 1" pipe (vs. 2" serial loop configuration) doubles the head loss and velocity
    • Actuator Valve

Overall Stats:

• overall pool volume: 32,427 gallons
• 8 hour turnover requires 67.6 gpm
• system head loss 50.58 ft hd loss
• water feature head loss 64.7 ft hd loss

Details as to Head Loss: PDF shows how I attempted to calculate headloss.

Concerns at this point:

1. Can a system have too low velocity to function properly?
   1. Both return and supply is under 3 ft /sec.
2. Do I have enough suction capacity to run both system pump and water feature pump?
   1. I have duplicated the suction capacity on both the water features and the system pump head loss calcs to have a suction component to figure total system head loss each.
3. Are pipe sizes too large?
   1. Compared to most that I am learning, most pool piping is around the 2” size. As you see on the calc’s pdf, I am using 3” suction piping, and 2.5” for the top and bottom returns and for the water features (subject to a switch to multi line or home runs).
4. How does one “right size” pipe to meet the needs of the bubblers and deck jets?
   1. I have read one needs approx.. 10 gallons per minute at 1’ head loss (for bubble itself) for the bubblers. I have 2.5” home run and symmetrical loop with 1.5” line to the bubbler. I have seen recommendations that 1.5” will service all three.
   2. I have been recommended 10-15 gpm for each deck jet. As mentioned above, questioning a 1” home run to 6 jets or use a 2.5” serial loop.

General note, we want all valves concealed so the home runs for the deck jets may be the way to go so we can place manual equalizing valves in the equipment room.

1. Do we need valves to adjust flow for the bubblers if we have the 2.5” (or recommended size)?
2. Should we have this engineered before proceeding with the plumbing? Any recommendations of who could review?
3. Any feedback on the calc’s?

Thanks so much for any help. Have loved the build so far and look forward to nailing this!

 

[Fastcarr]

Any recommendations on experienced individuals who could help specify pipe and hydraulics? Please share contact info.

 

[mas985]

Welcome to the forum!

• 8 hour turnover requires 67.6 gpm

Turnovers are irrelevant to proper pool maintenance. The flow rate you need is dependent only on the task. For just filtering and circulation, the lower the flow rate the better. However skimmers generally have a minimum flow rate where they will stop skimming properly.

1. Can a system have too low velocity to function properly?
   1. Both return and supply is under 3 ft /sec.
2. Do I have enough suction capacity to run both system pump and water feature pump?
   1. I have duplicated the suction capacity on both the water features and the system pump head loss calcs to have a suction component to figure total system head loss each.
3. Are pipe sizes too large?
   1. Compared to most that I am learning, most pool piping is around the 2” size. As you see on the calc’s pdf, I am using 3” suction piping, and 2.5” for the top and bottom returns and for the water features (subject to a switch to multi line or home runs).
4. How does one “right size” pipe to meet the needs of the bubblers and deck jets?
   1. I have read one needs approx.. 10 gallons per minute at 1’ head loss (for bubble itself) for the bubblers. I have 2.5” home run and symmetrical loop with 1.5” line to the bubbler. I have seen recommendations that 1.5” will service all three.
   2. I have been recommended 10-15 gpm for each deck jet. As mentioned above, questioning a 1” home run to 6 jets or use a 2.5” serial loop.

1. No

2. Pumps should always have individual suction lines going from the pool to the pump. But why do you need a separate water feature pump? How much flow rate do the deck jets require? A full size VS pump can handle quite a bit of flow (100 GPM) on decent sized plumbing (2").

3. It doesn't hurt anything to have very large pipe although it may not have much benefit either. Anything below 6 ft/sec at maximum RPM is generally sufficient pipe size. But don't forget that flow is split among parallel lines. So unless you plan on isolating return and/or suction lines, this will reduce water velocity.

4. Should be based upon a target flow rate and velocity. If each bubbler needs only 10 GPM that is 30 GPM total and if the maximum velocity target is 6 ft/sec, then 1.5" pipe is sufficient for that function. But make sure the 10 GPM comes from the manufacture. Sometimes they will give different flow rates for different bubbler heights.

1. Do we need valves to adjust flow for the bubblers if we have the 2.5” (or recommended size)?
2. Should we have this engineered before proceeding with the plumbing? Any recommendations of who could review?
3. Any feedback on the calc’s?

1. I would
2. By a licensed hydraulic engineer? Probably overkill. You should be fine as long as you target reasonable velocity (6 ft/sec) at pump full speed.
3. Who did them? In reality, it just doesn't matter all that much as long as you target reasonable velocity (6 ft/sec) at pump full speed. Also, it looks like the sheet is adding head loss of parallel runs which is incorrect.

Also, with two skimmers and deep returns, I might be more incline to skip the main drain. It won't add any value.

 

[ajw22]

Do you intend to use the suction ports on the Venturi skimmers?

If no, where will pump suction come from?

If yes, have you seen the Installation Manual says if the suction port is plumbed and used instead of the venturi, the suction flow is rated for a minimum of 25 GPM and a maximum of 55 GPM.

https://aamfg.zendesk.com/hc/en-us/article_attachments/4405625320973/quikskim-ultra_installation_20210701.pdf

That is a pretty tight range and with a VS pump it can be run at maximum electrical efficiency below 25 gpm and with your water features above 55 gpm.

There are much better ways of cleaning a pool then vacuuming through a skimmer.