Pool Pump Gallons per Minute

I need help in computing the Galons per minute pumped by my Century A.O. Smith B858 56Y Square Flange 1-1/2 HP Full Rated Pool and Spa Pump Motor. I have two skimmers and a main drain

Skimmer1=50’

Skimmer2=50’

Main Drain = 56’

Average Head = 52’

Once I find out the GPM I can complete the formula to calc how long to run the pump every day on my 24,000 gallon pool.

Thanks for your help

Hello Yosemite - If you can provide the feet of head and model of the pump (not motor), we can advise you on the GPM.

Check out our guide on “How Do I Calculate Feet of Head for My Pool”.

You can post a picture of the complete pump if you are not sure of the make and model,

forum

I thought I gave you “feet to head” in my initial question AND the pump model - what’s missing?

Here is a picture of label on pump

The feet of head you gave me is just an average of your suction side lines. That is not the correct way to get feet of head. I provided a link to a guide that properly explains how to calculate feet of head.

Also, you provided information about your motor. That motor is used on several pumps. We need to know the make and model of the pump.

pump

Wow, I still have a lot to learn about this stuff. I just moved into a house with a pool and have no history of the equipment or use of it. I may still need your help in figuring out the feet of head. I’m attaching photos which may help you to guide me in figuring it all out.

Here is an overview of all the 1 1/2" pipes going in/out of the pool equipment shed

I have two skimmers each about 50’ away and about 1’ higher in elevation than pump. I have no idea how many 45 or 90 degree angles there are on any of the pipes.

I have TWO main drains in the deep end of the pool so that would be about 7’ below the pump (=8-1).

There are two inputs between the waterfalls at the deep end of the pool - see image

So counting the waterfalls which can be on/off they are about 56 and 60 feet from the pump.

This is the best I can do to calculate head. Now the pump…

I realize this is sketchy but I just want to know how long to run the pump in swim season. And can I just run it a couple hours a day in the winter when not in use and to prevent freezing - I live in a warm climate in Athens GA

You’ll want to run the pump long enough to turn the body of water over once a day. The normal run time for residential pools is 8 hours per day.

As far as the feet of head, we have another method that you could try. It involves using a pressure gauge and vacuum gauge on the pump. The how to guide on “How to Measure TDH with Gauges” will walk you through the steps.

Now that we know the pump is an Ultra Flow, all we need is the feet of head measurement and we can determine the GPM.

Thanks - I’ll just go with the “normal” run time. I very much appreciate all your help.