Pump Run Time and SWG

[Blancmik]

Recently put in a pool and have appreciated the feedback and support of the forum. Not sure I would have survived this long without the feedback on startup, equipment, testing, etc.

What I'm still not clear on is the relationship between pump runtime and the SWG. I "feel" like I want to run the pump a long time at a slow speed to keep the water clean, but I'm not fully understanding what I should be doing.

I'm currently scheduled to run my pump from 7am to 9pm @ 1850 RPM. The Builder set me up at 2250 RPM for 12 hours. Based on my rudimentary math, I'm pushing a similar number of gallons through the filter with my longer run time and saving energy as the watts is ~300 vs ~800 @ 2250.

Any guidance on determining the right balance between RPM, SWG longevity, power usage and general feedback on keeping water moving?

Thank you!

 

[ajw22]

Determine Pump Run Time

To figure out how many hours you need to run your pump, you need to know how fast your pump works. You can find this here.

www.troublefreepool.com

Your IC40 cell will generate 3ppm of CL in 5 hours running at 100%. That is about your minimum pump runtime. Anything more then that is up to you for more hours of skimming. Some folks run their pump 24/7 at low speed. A VS pump costs very little running that way.

Minimum pump speed is whatever closes the IC40 float switch and turns off the No Flow light. Typically around 1500 RPM.

If you run your pump 24/7 at 1500 RPM with the IC40 at 20% you will generate 3ppm of CL a day.

Any pump runtime and SWG % that generates the same amount of CL affects the cell longevity the same way. Pump RPM does not affect the cell longevity.

 

[Blancmik]

@ajw22 Thanks for the quick response. Regarding your comment on the runtime vs SWG %... are you saying that there is a correlation between runtime and SWG%, so that running at a low % for a high number of hours vs a short time at a high percentage = equivalent wear on the SWG?

Is there any advantage to running at a higher RPM? At 1500 RPM, I'm only using ~225 watts. Is that better over 20 - 24 hours? Its clear to me that running for longer times at lower speeds is optimal from an energy usage perspective... what else do I need to consider?

24 hours at 1500 RPM (225 watts) = 5200 watts
14 hours at 1850 RPM (300 watts) = 4200 watts
12 hours at 2250 RPM (~800 watts) = 9600 watts

 

[ajw22]

@ajw22 Thanks for the quick response. Regarding your comment on the runtime vs SWG %... are you saying that there is a correlation between runtime and SWG%, so that running at a low % for a high number of hours vs a short time at a high percentage = equivalent wear on the SWG?

Correct.

Is there any advantage to running at a higher RPM? At 1500 RPM, I'm only using ~225 watts. Is that better over 20 - 24 hours? Its clear to me that running for longer times at lower speeds is optimal from an energy usage perspective... what else do I need to consider?

24 hours at 1500 RPM (225 watts) = 5200 watts
14 hours at 1850 RPM (300 watts) = 4200 watts
12 hours at 2250 RPM (~800 watts) = 9600 watts

No advantage for the SWG running at higher RPMs then what the Flow Switch needs.

You may need higher RPMS in your pool for skimming.

 

[MattyJ]

@ajw22 Thanks for the quick response. Regarding your comment on the runtime vs SWG %... are you saying that there is a correlation between runtime and SWG%, so that running at a low % for a high number of hours vs a short time at a high percentage = equivalent wear on the SWG?

Is there any advantage to running at a higher RPM? At 1500 RPM, I'm only using ~225 watts. Is that better over 20 - 24 hours? Its clear to me that running for longer times at lower speeds is optimal from an energy usage perspective... what else do I need to consider?

24 hours at 1500 RPM (225 watts) = 5200 watts
14 hours at 1850 RPM (300 watts) = 4200 watts
12 hours at 2250 RPM (~800 watts) = 9600 watts

Wouldn't these numbers be more accurately reported as watt hours (Wh) [or kilowatt-hours (kWh)] ?

24 hours @ 225 watts = 5200 watt-hours or 5.2 kWh
14 hours @ 300 watts = 4200 watt-hours or 4.2 kWh
12 hours @ 800 watts = 9600 watt-hours or 9.6 kWh

If each of these run times are equivalent for CL generation then it looks like the 14 hours @ 1850 RPM would be the best for energy cost. Not sure if there are other variables involved.
Cheers

MattyJ

 

[ajw22]

Wouldn't these numbers be more accurately reported as watt hours (Wh) [or kilowatt-hours (kWh)] ?

24 hours @ 225 watts = 5200 watt-hours or 5.2 kWh
14 hours @ 300 watts = 4200 watt-hours or 4.2 kWh
12 hours @ 800 watts = 9600 watt-hours or 9.6 kWh

If each of these run times are equivalent for CL generation then it looks like the 14 hours @ 1850 RPM would be the best for energy cost. Not sure if there are other variables involved.
Cheers

MattyJ

Why not 12 hours or 14 hours @1500 RPM?

What is your cost per KWH? Mine is about .15. So 5.2kWH/day = .78/day or $23/month Diffence between 24 hour run and 14 hour run is less then $4/month. For that cost I would keep my water being skimmed 24 hours a day.

 

[Blancmik]

@MattyJ I believe your display of the watts is correct.

@ajw22 Regarding your question "Why not 12 hours or 14 hours @1500RPM?" It appears from a cost perspective the difference is a couple of dollars a month (my electricity is about 10.4 center p/kWh). Unless I am running the vacuum and flow is enough to operate the flow sensor on the SWG, is there any other reason to run at a higher RPM?

I've seen threads where people say its best to run 24/7 at a low RPM to keep the water flowing and others who run at a mid level RPM for a couple of hours a day. I'm just not comprehending the pros/cons behind each option.

Thanks for bearing with me!

 

[ajw22]

I've seen threads where people say its best to run 24/7 at a low RPM to keep the water flowing and others who run at a mid level RPM for a couple of hours a day. I'm just not comprehending the pros/cons behind each option.

Whatever works for you and your pool is ok. Different people have different priorities. Different pools live in different environments and are designed differently. Some people like their pool skimming and their SWG generating CL 24/7. Others want to minimize energy usage.