Pump and flow experts, need some input

[rhedayi]

Recently I had a contractor install an ecostar 3400vsp. It replaced a whisperflo 2hp pump. I am convinced the pump is undersized or underpowered or perhaps it was not a good idea to swap in a vsp for the 2hp pump.

Here is the setup.

House is on a hill so backyard is sloped

Pebbletech pool that is a rectangle, 15.5 by 35 feet, the last 6 feet is a 6 inch Baja reef. It is only 3 feet deep at the shallow and goes to 5 feet deep. My best guess estimate is about 13500 gallons in the pool. Spa is 7x7, 3 deep and a sitting platform all around. My guess is it is 1000 gallons.


Attached is a pic before I had the pool resurfaced, pool currently full and operational. Way in the upper right side of the pic, you can see a short wall, it houses the pool pump equipment. It sits approx. 12 feet above the water line of the pool.

After the install, contractor asked me to play with it and see if I could optimize flow and reduce pump rate etc.

I am convinced the water flow is way low, so I called him out. He decided to place pressure gauges to determine head pressure etc.

We wrote all these values down...
at prime, pressure reading at pump was 22 and in the filter tank 16
at 2700 rpms pump pressure 18 filter 10
at 2000 rpms pump pressure 12 filter 5

we called Hayward to try to guess flow rates....they told us it is impossible and you have to just play with the pump and see how it goes.

How can I estimate the flow in this setup ? Any help is appreciated.

 

[jblizzle]

Why does the flow rate matter? Have you read the article in the How To section Pool School about determining pump run time?

My concern world have been that you switched to a significantly smaller pump which may not run the spa jets well enough. If they are sufficient for you, then the pump is fine. Ideally you want to run at very low speeds to save on power costs.

 

[rhedayi]

Thank you for the reply. I was concerned that the flow rate is low and I wont be able to get 1 or 2 turnovers per day. Spa jets are fine, besides I can arrange a different rate to each function. VSPs seem to save money by operating at very low rpms, it seems when I reduce the rpms to 1600-1700 range there is almost no flow.

 

[jblizzle]

Turn over is meaningless, read the article.

If water is moving, then the flow is fine. You can probably run down around 1000rpm.

 

[rhedayi]

Found it
Pump Run Time

Conventional wisdom is that most pools need 1-2 turnovers per day. However, studies have shown that most pools need far less run time than that and can usually get away with 3-4 hours of run time per day. However, for two speed or variable speed pumps on low speed, the skimming action tends to decrease so the run time may need to be increased to compensate. The bottom line is to run your pump long enough to keep chlorine at recommended levels and to keep the pool clean enough for your own personal preference.


Great, I will reduce the pump rpms some more.