NEW to VS pumps - How to calculate turnaround?

[southflorida427]

I just replaced my old single speed pump with a Hayward TriStar 1.85HP VS pump.

I have 1.5" plumbing.

How can I calculate the flow rate GPM at XX RPM with this pump and this plumbing size?

My goal is to use this information to schedule my different speeds and intervals to move the 13k gallons of water every 24hours.

PS: this is one of a series of posts I'm creating for different questions for my new VS pump.

 

[mknauss]

Keep all your questions in one thread.
Turnover is a myth. You need to run the pump long enough to mix the chlorine you add each day and skim the surface.

 

[mknauss]

Try a prime speed of 2500 rpm. If that works, that is the max rpm you will need. You can try lower if you like.

 

[southflorida427]

Keep all your questions in one thread.
Turnover is a myth. You need to run the pump long enough to mix the chlorine you add each day and skim the surface.

In this case, I need to change the question, I want to save the most money while maintaining a healthy pool. I have an SWG to run and also a suction pool cleaner.

Can u please help me figure out the intervals and speed I should be running?

 

[Jimrahbe]

427,

Your minimum speed is whatever turns your SWCG on plus about 100 RPM.. If you run your pump long enough to generate the amount of chlroine you need, you will have run as long as you need to run. You can run longer if you wish, but that is up to you.

The only other thing you need to think about is skimming. I suspect that your SWCG speed will also be enough to keep your pool skimmed, but if not, you can run for a couple of hours at a faster speed.

Thanks,

Jim R.

 

[ajw22]

What time period do you run your suction cleaner?

What pool controls do you have for automation, the pump speeds, and your cleaner?

Is your pool in a cage?

What runtime is required for your SWG?

How did you run your previous pump?

 

[JJ_Tex]

You run your pump for multiple reasons, so I would first see how low you can go and have that be your baseline:
1. Skimmer - Look at the weir door and see the lowest rpm you can run and have the door still be open
2. SWG - What is the lowest rpm you can run before the flow sensor shuts it off

Pick the higher RPM of the above and have that be your low speed. There may be times of the day where you want higher RPMs for things like water features, cleaners, extra skimming. There is no magic answer on those, but play around and see what works for you.

The last thing to do is to figure out how long to run it for. Many people (like me) run theirs on low speed 24/7 since it hardly uses any electricity at lower speeds so you might as well get the benefit of making chlorine, filtering, and skimming from the pump.

 

[Jimrahbe]

427,

Your SWCG will make about .58 ppm of FC per hour of run time at 100% output.. So, to generate 3 ppm of FC will take about 5.5 hours of pump run time. Or, 11 hours if the cell is set to 50%.

This assumes your pool is using 3 ppm per day, which is what it probably uses in the summer, this time a year, it should be a lot less.

I would start by running the pump at your "SWCG speed" for 10 hours a day and your cell set to 30% and then check your FC every day for a week and see if you need to decrease or increase your chlorine production.

Each pool and location is a little different.. We can give you a a starting point, but it will be up to you to fine tune your operation.

Thanks,

Jim R.

 

[southflorida427]

What time period do you run your suction cleaner?

What pool controls do you have for automation, the pump speeds, and your cleaner?

Is your pool in a cage?

What runtime is required for your SWG?

How did you run your previous pump?

Before changing the pump I was doing two 4 hour cycles, one in the morning starting at 9 am and another in the evening starting a 6 pm, for a total of 8 hours a day of run time. SWCG was set at 90% doing those 8 hours. The cleaner was always in the pool hooked to the skimmer port.

I don't have any other automation at the moment than the new TriStat internal controls and keypad and the SWCG dial for power %.

 

[southflorida427]

OK lots of good comments and suggestions (as always); thank you.

I'm going to start by figuring out the lowest RPM that would make my SWCG flow switch happy. Then add the suggested 100 RPM buffer.

Once that is under control I'll come back and continue the rest of the conversation (max RPM for 1.5" plumbing and minimum time to run suction cleaner at max RPM).

 

[ajw22]

What HP was your old pump?

You have to figure out what pump speed gives you effective cleaning and how long you need to run your cleaner for. That may be 2400-2800 RPM. Then the remainder of the time you need to run your pump to generate the necessary chlorine.

Try around 1500 RPM and see if your SWG is happy.

Then adjust your SWG runtime and % to meet your FC needs. You can run longer at lower % or shorter at higher %.

 

[southflorida427]

What HP was your old pump?

You have to figure out what pump speed gives you effective cleaning and how long you need to run your cleaner for. That may be 2400-2800 RPM. Then the remainder of the time you need to run your pump to generate the necessary chlorine.

Try around 1500 RPM and see if your SWG is happy.

Then adjust your SWG runtime and % to meet your FC needs. You can run longer at lower % or shorter at higher %.

I had a Pentair WhisperFlo 1.5HP.

I'll try your suggestions.

Thank you.

 

[markayash]

You will save a lot of money, VS pumps are a lot more energy efficient. I measured amps between speeds and it wasn’t a huge jump. Don’t worry too much over a few RPM.

 

[Homebrewale]

Keep all your questions in one thread.
Turnover is a myth. You need to run the pump long enough to mix the chlorine you add each day and skim the surface.

And run a heat pump if a person has one installed. I will note this is not the case for the OP but can be for other pool owners.

 

[southflorida427]

I've set two timers, the main one at 1200 RPM from 9 am to 9 pm (12 hours), and then another one that kicks in the middle of it at noon for 2 hours of 2500 RPM for the suction cleaner.

SWCG will turn on at 10 am and go to sleep at 8 pm for a total of 10 hours @ 55% of SWCG, which will produce around 3.2 ppm.

Will keep an eye on it for a couple of days.

Thank you all.