Running my pump at 2500rpms for 4.5 hours a day, can I reduce the RPMs?

[Skenn81]

I know there is a lot of "it depends" but I don't know how to do the math or calculate this all out.

As sig says it is a 15,000 sqft pool in Florida, screened in, lots of sun all day. Variable speed Pentair pump so I can have it do whatever. I set it at 2,500rpms a year ago because it seemed like a fine thing to do and reduced the run time based on the readings here at around 4 hours a day is enough to get the chemicals where they need to go. No real problems outside of an oopise two weeks ago that was documented here.

In an effort to try to cut back on electricity and just be generally more efficient in my energy use I come to the pool pump. I haven't set it for any good reason and was trying to see if I could reduce it to 2,000 for now or even lower. It's a variable speed pump the previous owners put in that does absolutely no variation at all, it's either on or off, so wondering how we can figure out if we can take advantage of this and reduce it down.

 

[jimmythegreek]

Do you have a SWG? You only need a short time to mix chemicals. Your run time is based on skimming the pool to clean surface debris and if you need to create chlorine from salt If you have a cell. You can easily go to 1500 or even less. I run 1200 at about 8hrs in peak of summer and 6hrs early and late season

 

[PoolGate]

Yes for sure. I run mine at 2k rpms unless the heater calls for more. With a "chlorine" pool I assume you do not have a saltwater chlorine generator. But even so, 2k is enough to satisfy their flow switches. Do you run a cleaner? Cleaners do a lot to keep water circulated.

 

[Skenn81]

Answering questions... No SWG, liquid chlorine only. A Polaris vac drives around in the pool whenever the pump is on. Surface is clear for the most part because of the screened in enclosure. Just tiny bugs that can get through the screen and the occasional big one that finds its way in between the gutter lines.


By the math, is 1200 for 8 hours the same as 2400 for 4 hours?

I will reduce down to 2000 this weekend and observe as a first step.

 

[Jimrahbe]

81,

Sounds to me like you believe in the "turnover" theory, which says you have to turnover your pool water x times a day... It is just not true. Chemicals keep your water clear, not the number of times you push water through the filter. The filter is just there to capture the junk that falls into your pool.. With a screen enclosure, you should not have much of an issue.

Thanks,

Jim R.

 

[Skenn81]

I was on the turnover theory until last year when I read an article on TFP which said it's just about runtime. It was at 8 hours a day from previous owner and I moved it down to 4 and a half.

Now that I am down at a reduced runtime I am trying to reduce the RPMs if they are also not needed to be so high.

I am, though, still under the impression that I need the water to move around so doing things like added liquid CL or acid is needed to distribute it evenly and keep the pool levels correct.

 

[Jimrahbe]

81,

I run my pump at 1200 RPM and it works fine for me... You will just need to experiment and see what works best for you.

I suggest you run at 1500 for 4 hours and see how that works.. and then adjust from there.

Thanks,

Jim R.

 

[Oly]

You are going to have to play with pump speeds and watch the results. Watch your pool cleaner work (sounds like a suction side unit) and find the best speed for normal cleaning. Watch the skimming action and find your minimum speed then find the optimum high speed for polishing the water surface. I start my pump at 2400 for 1.5 hrs then down to 1200 for 6 hours and finish with 2400 for 1.5 hours. My pump is only used for skimming and chem mixing. VS pumps are more efficient at moving water at lower speeds to a point, I believe below 1000 rpm efficiency falls off.
Have fun exploring your options.

 

[jstephens1]

also how much are you really saving? i have my VSP run 24 hours at 1200 RPM this uses 98 watts. based on my power costing 11 cents per KW it comes out to 28 cents a day or about $8.50 a month

 

[Skenn81]

Okay I tried a bunch of different settings and most of them are having the same result, which is the Polaris isn't moving. 1500, 1750, and 2000. It's not a suction unit, it works off of a dedicated return port so the valve needs to be split between either the normal returns for water circulation or the Polaris port. If I close off all of the return valves the Polaris moves but I don't want to be out there moving around that handle on a daily basis.

What I am thinking now is similar to Oly, in that I will have it run at 2500 for an hour a day to let the Polaris do it's thing, and then turn it down to 1500 for the remainder of the time.

 

[PoolGate]

Okay I tried a bunch of different settings and most of them are having the same result, which is the Polaris isn't moving. 1500, 1750, and 2000. It's not a suction unit, it works off of a dedicated return port so the valve needs to be split between either the normal returns for water circulation or the Polaris port. If I close off all of the return valves the Polaris moves but I don't want to be out there moving around that handle on a daily basis.

What I am thinking now is similar to Oly, in that I will have it run at 2500 for an hour a day to let the Polaris do it's thing, and then turn it down to 1500 for the remainder of the time.

You need to run at the highest RPM that any of your features needs while the pool is running. SWGs typically can run as low as 1000rpms, cleaners need more. You'd be better off investing in a nice electrically operated robot instead of the water powered cleaner.

 

[markayash]

I did some testing with my amp meter and on my 1.65 pure line every step down dropped about .4 amps or around 50 watts. I have a water fall and i kept going down until it wasnt flowing strong and ended up at 2100. For my cleaner i have mine set to run at 2100 20 hours a day and 2800 4 hours at night when power is cheaper. If it needs a extra cleaning i just push override.
Hoping to switch to a robot when this polaris dies again but just rebuilt it this past fall.
But i run mine 24x7 just becaue i like the sound of the waterfall and its not using a lot more power then a old style 100 watts light bulb

 

[BowserB]

I had a pressure side cleaner that ran with a booster pump. In addition the booster pump required the main filter pump to be at 2800 or higher, all to run a crappy Pentair Kreepy Krauly feeble pool cleaner. I dumped the Kreepy Krauly and replaced it with a robotic. Now I run the Pentair VSF pump at 1725 rpm (1/2 half speed) drawing 298w from 8am to 8pm. At that speed it is quiet and moves 26 gpm through the filter. That's 18,720 gallons per day and is probably excessive, but the speed keeps water trickling over the spa spillway at a rate my wife approves of. I'm thinking of cutting back to 10 hours a day.

 

[Skenn81]

Electric? Why that over having one which runs off the pool itself? Does that mean I need to have an extension cord running into the pool at all times to keep it going? Do you roll it all up when the pool is used?

 

[Jimrahbe]

81,

Robots are powered by low voltage DC and are not a shock hazard... If you like swimming in the pool with your kreeppy crawler, then there is no reason to remove the Robot when you swim.. I remove mine, not for any safety reason, but I think having any kind of cleaner in the pool when I am swimming takes away the ambience that I am shooting for...

Thanks,

Jim R.

 

[Skenn81]

What do you plug it in to? What's the DC power source?

 

[Jimrahbe]

81,

The Robot has a power supply that stays on the deck away from the pool... It takes 120 volts AC input and converts it into about 30 volts DC.. which powers the robot around the pool.

Thanks,

Jim R.

 

[Skenn81]

Well this experiment was a total failure. RPMs back up to 2500 and the Polaris is moving around as it was before.

What a bummer. Thought i was going to save a couple cents on electricity and I am right back to where I started.

Jim, so the robot power supply is plugged into a regular outlet someplace outside? Can the converter get wet or do you need to pack it up any time a storm would be rolling in, which down here is almost daily.

 

[Jimrahbe]

81,

The power supply is weather "resistant" but not waterproof.. In my case, I have my power supply mounted to the wall of my house. About two feet off the ground and under the overhang of the roof. It can get a little water blown on it, but it does not get soaking wet.

I have another one as a rent house and I just built a little "dog house" for it, to keep it out of the weather..

Thanks,

Jim R

 

[Skenn81]

Random update..

So it turns out the Polaris needed a bit of an overhaul. I took a closer look at it one day and noticed the gears were crunchy and the wheels were not spinning smoothly. Brought it into the shop and $155 later worth of belts and bearings its back to running smoothly.

The RPMs are now down to 2100 and it's still puttering along fine on the bottom of the pool. Going to try bringing it down to 2,500 next and continue to see how low it can go while still pushing it around.