Variable Speed Pump Schedule

SteveScanOctober 29, 2011

Hi all. Just wanted to share with you guys how we run our filter pump. We had an in-ground pool built this year (24,000 gallons, raised spa, Pentair Intelliflow pump, 2 skimmers, Polaris sweep, saltwater chlorinator). I wanted to minimize our electrical cost, so I installed a flowmeter and made some observations about how pump speed affects flowrate and electrical usage. What I learned is that minimum electrical usage occurs at minimum speed. At high speed (3450 RPM), one turnover takes 3.8 hours at a cost of $1.07. At minimum speed (1100 RPM), one turnover takes 15.9 hours and costs $0.22 (assuming $0.1 per KWH)

So, I run the pump as slow as possible. The saltwater chlorinator needs 30 GPM minimum which occurs at 1250 RPM so this is our low speed. We run the sweep (with booster pump) two hours a day. It runs at the correct speed (28-32 RPM) with the filter pump at 3000 RPM, so this is our high speed. I could probably remove the flow restrictor in the sweep line and slow the pump, but would make for less surface cleaning action at the skimmers. We enjoy the sound of the spa fountain in the evening, which is nice at 1500 RPM, so this is our medium speed.

During the swim season, we filter the water two turnovers per day. Off-season, we filter the water one turnover per day. To get this, we run at low speed 16 hours during the swim season and 3 hours in the off-season.

Here is the schedule:

Swim Season: Two turnovers total

7 - 8 am Low speed (to start up)

8 - 10 am High speed (to sweep and skim)

10 am - 5 pm Low speed (to filter)

5 - 8 pm Medium speed (to enjoy)

8 pm - 4 am Low speed (to filter)

4-7 am Off

Off-Season. One turnover total.

7 - 8 am Low speed (to start up)

8 - 10 am High speed (to sweep and skim)

10 am - 12 pm Low speed (to filter)

5 - 8 pm Medium speed (to enjoy)

8 pm - 7 am Off

At 1250 RPM, flow is 30 GPM and power is 236 Watts

At 1500 RPM, flow is 39.9 GPM and power is 281 Watts

At 3,000 RPM, flow is 91.5 GPM and power is 1870 Watts

Notice that going from low to high speed, flow increases by 300% and power by 800%. That is why minimum electrical cost occurs at minimum speed.

Flow is per a Cole-Parmer S-05611-14 flowmeter

Power is per the Pentair pump

Thank you for reporting this comment. Undo
poolguynj

Please share your plumbing size, other equipment models, spa jets, etc...and what pool sweep you are using.

Scott

    Bookmark   October 29, 2011 at 2:17PM
Thank you for reporting this comment. Undo
fyton2v

Interesting post. I second what Scott said...

    Bookmark   October 30, 2011 at 12:09AM
Thank you for reporting this comment. Undo
mas985

The Intelliflo should be able to go down to 400 RPM but what you will find is that the gallons/watt-hr will start to drop again below about 800 RPM so the most efficient speed is usally between 800 and 1200 RPM depending on the plumbing which I think you found out.

    Bookmark   October 30, 2011 at 11:48AM
Thank you for reporting this comment. Undo
ncrealestateguy

Why did you install a flowmeter? The pump has a flowmeter and watt meter built in.

    Bookmark   November 4, 2011 at 7:04AM
Thank you for reporting this comment. Undo
poolguynj

@ncreal, only the VF has that. The VS and SVRS models do not show GPM rates, just RPM and power (Watts).

Scott

    Bookmark   November 4, 2011 at 9:17AM
Thank you for reporting this comment. Undo
obrionusa

If you like your pool you have to like your light bill. My bill jumps up about $60 a month when its running. Thats why its on a timer.

    Bookmark   November 8, 2011 at 5:24AM
Thank you for reporting this comment. Undo
poolguynj

@obrionusa,
That seems high. I would bet you that we could cost effectively lower your pool's energy consumption if we knew more about your pool. Having a timer is not the only factor that needs to be considered. BTW, the timer used in the original poster's system is built in.

There is pool size, plumbing size, power costs, features, and so on.

Not all pool pumps are the same. Not by a long shot. Generally speaking, bigger is usually not better.

Scott

    Bookmark   November 8, 2011 at 6:33AM
Thank you for reporting this comment. Undo
brg88tx

interesting, my intelliflo pulls about 210 watts at 1500 rpm and i thought that was high because i've seen some others who reported slightly under 200 watts at 1500 rpm. now i see you show 281 watts for 1500 rpm. i guess the pipes and configuration makes this vary greatly.

    Bookmark   November 9, 2011 at 3:13PM
Thank you for reporting this comment. Undo
poolguynj

As does the filter's state. As a filter gets "dirty", pressure will rise, though with VSPs, the usual 10 PSI change normally expected is reduced to about 3 PSI or so because of the reduced flow.

Scott

    Bookmark   November 9, 2011 at 5:12PM
Thank you for reporting this comment. Undo
rmrc12

For reference my newly installed Intelliflo (model 011018) pulls about 300 watts at 1700rpm (about 50 gal/min) where I have mine set. Of note though, the filter is very dirty and I'll clean it this weekend. Curious to see if the power usage will drop with a clean filter.

    Bookmark   November 10, 2011 at 11:00AM
Thank you for reporting this comment. Undo
poolguynj

It will. Less friction.

Scott

    Bookmark   November 10, 2011 at 12:33PM
Thank you for reporting this comment. Undo
ncrealestateguy

What if the pump is about 5 feet below grade of the pool?

    Bookmark   November 10, 2011 at 1:13PM
Thank you for reporting this comment. Undo
mas985

A centrifugal pump will draw more power when the head loss decreases. The operating point moves to the right on the head curve, flow rates increase, and power draw increases.

With a VS and the same RPM, the pump will draw more power for the reasons mentioned above.

However, with a VF where the flow rate is constant, the power draw decreases because the drive reduces RPM to maintain the same flow rate (i.e. head curve drops because of lower RPM and operating point shifts to the right).

    Bookmark   November 10, 2011 at 1:17PM
Thank you for reporting this comment. Undo
mas985

The elevation of the pump does not affect power draw only the difference between suction head and return head. Suction head will decrease by 5 feet but return head will increase by 5 feet so there is 0 net change in total head.

    Bookmark   November 10, 2011 at 1:20PM
Thank you for reporting this comment. Undo
rmrc12

mas985 is absolutely correct. I just cleaned my filter. Before cleaning the wattage displayed was 315. After cleaning and adding Fiber Clear the wattage displayed is 365. Both readings are at 1700 rpm.

    Bookmark   November 10, 2011 at 8:19PM
Thank you for reporting this comment. Undo
poolguynj

But you're moving a lot more water now.

Scott

    Bookmark   November 10, 2011 at 8:24PM
Thank you for reporting this comment. Undo
trhought

I would also add that the Intelliflo VF will use more power when the filter gets dirty because the pump speed is automatically increased to maintain the same flow.

Never understood the VF offering....are there really any pool features that require such critical flow at the cost of more power consumption.

    Bookmark   November 10, 2011 at 10:41PM
Thank you for reporting this comment. Undo
ncrealestateguy

But trhought, the opposite is true too... when the filter is clean, and resistance less, I use less energy because the computer keeps the flow rate the same by reducing the wattage. The same is true for the four when my polaris cleaner is on. The resistance is less for it than the water going through the cleaner, so the energy used decreases quite a bit, even though my flow rate remains the same.

    Bookmark   November 11, 2011 at 6:31AM
Thank you for reporting this comment. Undo
rmrc12

@ncrealestateguy - It sounds like you have the Intelliflo VF. I didn't step up and pay the extra $$ for the VF so with the clean filter I plan to either leave the pump set at 1700rpm and cut the run time or reduce the rpm and keep the run time the same. I think I would save more energy by reducing the RPM and leaving the run time the same.

Separately, I switched over to a robotic cleaner so my filter cleaning interval should be much more spread out than when I used a suction side cleaner.

    Bookmark   November 11, 2011 at 9:29AM
Thank you for reporting this comment. Undo
domingos35

i run my VF from 5am to 4.30pm at 1100 rpm's and it uses 156 watts 24 GPM .my electric bill went down $60 dollars per month.love this pump

    Bookmark   November 12, 2011 at 8:57AM
Thank you for reporting this comment. Undo
trhought

ncrealestateguy and domingos....but as your filter gets dirty, your VF will use more power as speed is increased to compensate for the head loss...this is not true with a VS, 2 speed or 1 speed...power decreases and flow will decrease which gives the pool owner a signal that the filter should be cleaned without costing extra energy consumption.

    Bookmark   November 12, 2011 at 9:22AM
Thank you for reporting this comment. Undo
ncrealestateguy

I would rather keep my filter at a clean level, and have all my water features unaffected if the filter does get dirty.

    Bookmark   November 13, 2011 at 8:05AM
Thank you for reporting this comment. Undo
trhought

ncrealestateguy....but your filter is only at a clean level until you put it into service, then the VF starts increasing power each day.

    Bookmark   November 13, 2011 at 11:13AM
Thank you for reporting this comment. Undo
domingos35

i monitor the pumps speed and watts consumed on a regular basis and its almost always running between 1100 RPM's and 1150 RPM's.i clean the filter on a monthly basis

    Bookmark   November 13, 2011 at 7:43PM
Thank you for reporting this comment. Undo
ncrealestateguy

Trhought... where are you seeing this data that you quote? My RPMs and watts do not increase day by day until I clean my filter again.
I will clean my filter soon and document #s.

    Bookmark   November 14, 2011 at 6:33AM
Thank you for reporting this comment. Undo
trhought

ncrealestateguy...as head loss changes, the Intelliflo VF is designed to increase or decrease speed to maintain the same flow. As a filter gets dirty, the head loss increases which decreases flow. The VF senses this decrease in flow and increases pump speed to maintain the flow setpoint.

When you record your VF power, you'll find the power consumed with a dirty filter will be higher than what it is after cleaning.

If your pump was a VS, 2 speed or 1 speed, you would find the power is lower with a dirty filter ( from above rmrc12 reported a 50 watt difference with a VS). This is how pool pumps (a centrifugal pump design) behave when speed is constant and head loss increases. The VF, however, increases speed as the filter gets dirty which consumes more power.

When you post your power results before and after cleaning, please also post the rpm for each.

Clearly, the more frequently you clean the filter, you'll notice less power difference but with an Intelliflo VF, the dirty filter power will always be higher than the clean filter power...that't the way it was designed.

Hope this helps.

    Bookmark   November 14, 2011 at 9:12AM
Thank you for reporting this comment. Undo
ncrealestateguy

throught,
I know all of this... I am just saying that I must keep my filter fairly clean, because I just do not notice much of that increase that you are speaking of. Apparently, the same with domingos35.
And my water features do not deteriorate like they would with a VS.

    Bookmark   November 14, 2011 at 2:24PM
Thank you for reporting this comment. Undo
trhought

ncrealestateguy....if your experience is like domingos, then you do see a power increase...you may not notice it day-by-day, more likely week-to-week and certainly month-to-month...just keep that filter clean to avoid rising monthly utilities.

Guess it's personal preference...I would rather the water features and pressure gage tell me it's time to change the filter and know I'm using less energy while the filter is dirty. With the VF, you're paying the price for neglecting to clean the filter without having any obvious visual signals from your pool....the signals are more sublte...the VF display and ultimately the higher monthly utility bill if the filter has been neglected.

Just my 2 cents.

    Bookmark   November 15, 2011 at 9:10AM
Thank you for reporting this comment. Undo
davegvg

To the guys saying its running to fast or consuming too much power seems you are forgetting the chlorinator needs to see 30 GPM. That effectively is the lowest speed the OP should run.

The lowest any variable RPM/ Flow pump with a chlorinator should be set to is the chlorinators min GPM speed.

In a standard chlorinated pool the min speed should be the slowest speed that still gives actual skimming.

If set too slow like the pumps minimum speed there is a very real chance you get no skimming at all and the skimmer starts into a "bobbing cycle " vs. actually pulling a steady vacuum and skimming.

It doesn't matter how cheap the pump is to run if your pool is dirty all the time.

Uncle Dave

    Bookmark   April 13, 2013 at 3:57PM
Thank you for reporting this comment. Undo
poolnoobie123

thanks for all the great information you guys have posted

I am new to pool care and own a variable speed pump. pool is about 16000 gallons and we live in sunny southern California. I have a pool guy that keep the chemicals balanced and I add phos free once a week. the pump is running at 1300 rpm for 8 hours a night and 2400 for 4 hours - all while attached to a kreepy krauler sweeper. the water was just changed about 2 months ago and is getting murky and has algae. the pool guy wants me to run the pump at 3400 x 6 hours a day instead of at low revs since he feels I am not turning the water over fast enough. that seems excessive and defeats the purpose of the variable speed pump.

I don't know the pipe size. We use a solar cover about 3 days a week and the water temp is about 82 degrees. 1 caveat is that my dog (golden retriever) swims in the pool about 4 times a week.

Any suggestions?

Thanks in advance for all your input

    Bookmark   August 29, 2013 at 4:17PM
Sign Up to comment
More Discussions
Need help with pool re-plastering job problem
We had a pool replastered. Contractor disappeared for...
ou17776
Exceptional Pool Builders who build in Cleveland, OH area?
My wife and I are beginning the design stage of our...
jc_ufl
My pebble sheen finish is so uneven...
Our pebble sheen finish was completed on January 1st...
Susan Scearce
Small 3/4' mosaic waterline tile - mistake?
Hello, We're getting ready to sign our contract, and...
oakrunfarm
Newbie Hot Tub Owner - Questions On Chemicals
Hello, I am a first time hot tub owner and I'm in the...
gil_happy
Sponsored Products
Hillsdale Brookside 5 Piece Round Dining Room Set w/ Diamond Back Chairs
Beyond Stores
SuperArchimoon Floor Lamp by Flos Lighting
$9,995.00 | Lumens
Hydro Systems Danika 7341 Tub
Modern Bathroom
House of Troy Swingarm Pharmacy Antique Brass Floor Lamp
Lamps Plus
50" Modern Fan Velo Gloss White Hugger Ceiling Fan
Euro Style Lighting
Elite Cuisine Four-Slice Long Slot Cool Touch Toaster
$19.99 | zulily
Iron Curtain Rod - 26"-48" (2 brackets)
$69.00 | FRONTGATE
Chromaglo Spectrum LED Square Reflector Pendant
Lightology
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™