Upgraded pad to 2″, converted unused pressure-side vacuum line to return — Jumped from 35 GPM to 65+ GPM

[claygriffiths]

Hey all,

I became a pool owner last year and have quickly turned into a full-blown pool nerd — and a TFP evangelist.

With the size of our pool, I couldn’t help but feel like the flow was just too dang low.

I wanted to share my experience doing some pad-side plumbing upgrades this past week, since it was something I contemplated over and over.

Background:

• Pool size: 44×22 ft, 50,000+ gallons, 11.5-12 ft deep
• Pool age: Built in the ’60s or ’70s (hybrid pool: gunite/plaster floor with fiberglass walls — still hanging in there!)
• Underground plumbing:
  • 1.5” skimmer line — One skimmer for the whole pool. It's rough with how many trees we have. Betta SE has been helpful.
  • 1.5” main drain line
  • 1.5" return line going to two returns
  • (Now previously) unused 1.5" line that was a pressure-side vacuum with booster.
• Pump: Pentair IntelliFlo3 1.5 HP (2” union slip fit, 1.5" inside fit)
• Filter: Triton sand filter (not sure what the model is, the sticker is wearing off)
• Heater: Pentair MasterTemp 400
• Starting flow: ~35 GPM at 99% RPM. 39 GPM on a really, really good day.

What I Changed:​

• Suction side:
  • Installed Jandy 4715 3-way valve to combine the skimmer and main drain into a 2” trunk (previously 1.5"). This replaced two seized up, basic ball valves that I'm sure restricted flow.
• Return side:
  • Converted unused pressure-side vacuum line into a new dedicated 1.5” return
  • Added a second Jandy 4715 3-way to split the 2” return trunk into two 1.5” returns (existing and converted vacuum line)
  • Installed full-port Jandy BVSU015 1.5” ball valves on each return line (no room on suction).
• Other:
  • Re-plumbed all pad piping to 2” PVC (pump ➔ filter ➔ heater ➔ returns)
  • Installed a flow meter (H2Flow) on the return trunk

Preliminary Results:​

• Flow
  • 65–72 GPM at 99% RPM (60-70% improvement)
  • 35 GPM at 65% RPM
• Filter pressure dropped:
  • From ~20-22 psi ➔ ~14–15 psi at the same RPM
• Turnover time:
  • I'd be lucky if I could get the pool to turnover once in 24 hours. Now, I can turn it over almost twice in a day if running full-blast.
• Usability:
  • I can now control the flow of both suction and returns much more easily.

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At this point, I'm still dialing in the new return port's eyeball and the return Jandy BVSU015's to try to get a nice circulation pattern.

Since I’m still a pool novice, I’m not here to blindly recommend this — just wanted to share my numbers and experience as a bit of a “science experiment.”

Please feel free to pick this apart and tell me where I went wrong or what I could improve. In the future, I would love to add a SWG and go cartridge to save some space and make future plumbing projects easier.

 

[jfmorris]

I am currently in the middle of relocating my pool pump, filter, and adding a heater, and my pool is of similar age as yours, with 1.5" supply lines from a single skimmer and main drain, and a single 1.5" return that appears to hit a return in the corner of the deep end first, then continue around the pool to a diagonally opposite return in the shallow end.

I've already decided and purchased new valves and fittings to do what you've described, so that everything I can do is 2" above ground, but will be stuck going with a single return line to where it transitions back to 1.5" underground, in the current pump location.

My question for you is with the 3 way on the two returns you now have, why did you also put a ball valve on the return lines, presumably past the 3 way? Seems a danger of someone shutting one or the other of those off, and with the 3 way in the wrong position, causing the pump or filter to get damaged with no return open?

I had a similar setup in the past on my 2 supply lines, but killed the two individual valves in favor of a 3 way into the pump.